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December 16, 2024

Cleo File Transfer Vulnerability: Patch Pitfalls and Darktrace’s Detection of Post-Exploitation Activities

File transfer applications are prime targets for ransomware groups due to their critical role in business operations. Recent vulnerabilities in Cleo's MFT software, namely CVE-2024-50623 and CVE-2024-55956, highlight ongoing risks. Read more about the Darktrace Threat Research team’s investigation into these vulnerabilities.
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
Maria Geronikolou
Cyber Analyst
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16
Dec 2024

File transfer applications: A target for ransomware

File transfer applications have been a consistent target, particularly for ransomware groups, in recent years because they are key parts of business operations and have trusted access across different parts of an organization that include potentially confidential and personal information about an organization and its employees.

Recent targets of ransomware criminals includes applications like Acellion, Moveit, and GoAnywhere [1]. This seems to have been the case for Cleo’s managed file transfer (MFT) software solutions and the vulnerability CVE-2024-50623.

Threat overview: Understanding Cleo file transfer vulnerability

This vulnerability was believed to have been patched with the release of version 5.8.0.21 in late October 2024. However, open-source intelligence (OSINT) reported that the Clop ransomware group had managed to bypass the initial patch in late November, leading to the successful exploitation of the previously patched CVE.

In the last few days Cleo has published a new vulnerability, CVE-2024-55956, which is not a patch bypass of the CVE-2024-50623 but rather another vulnerability. This is also an unauthenticated file write vulnerability but while CVE-2024-50623 allows for both reading and writing arbitrary files, the CVE-2024-55956 only allows for writing arbitrary files and was addressed in version 5.8.0.24 [2].

Darktrace Threat Research analysts have already started investigating potential signs of devices running the Cleo software with network traffic supporting this initial hypothesis.

Comparison of CVE-2024-50623 and CVE-2024-55956

While CVE-2024-50623 was initially listed as a cross-site scripting issue, it was updated on December 10 to reflect unrestricted file upload and download. This vulnerability could lead to remote code execution (RCE) in versions of Cleo’s Harmony, VLTrader, and LexiCom products prior to 5.8.0.24. Attackers could leverage the fact that files are placed in the "autorun" sub-directory within the installation folder and are immediately read, interpreted, and evaluated by the susceptible software [3].

CVE-2024-55956, refers to an unauthenticated user who can import and execute arbitrary Bash or PowerShell commands on the host system by leveraging the default settings of the Autorun directory [4]. Both CVEs have occurred due to separate issues in the “/Synchronization” endpoint.

Investigating post exploitation patterns of activity on Cleo software

Proof of exploitation

Darktrace’s Threat Research analysts investigated multiple cases where devices identified as likely running Cleo software were detected engaging in unusual behavior. Analysts also attempted to identify any possible association between publicly available indicators of compromise (IoCs) and the exploitation of the vulnerability, using evidence of anomalous network traffic.

One case involved an Internet-facing device likely running Cleo VLTrader software (based on its hostname) reaching out to the 100% rare Lithuanian IP 181.214.147[.]164 · AS 15440 (UAB Baltnetos komunikacijos).

This activity occurred in the early hours of December 8 on the network of a customer in the energy sector. Darktrace detected a Cleo server transferring around over 500 MB of data over multiple SSL connections via port 443 to the Lithuanian IP. External research reported that this IP appears to be a callback IP observed in post-exploitation activity of vulnerable Cleo devices [3].

While this device was regularly observed sending data to external endpoints, this transfer represented a small increase in data sent to public IPs and coupled with the rarity of the destination, triggered a model alert as well as a Cyber AI Analyst Incident summarizing the transfer. Unfortunately, due to the encrypted connection no further analysis of the transmitted data was possible. However, due to the rarity of the activity, Darktrace’s Autonomous Response intervened and prevented any further connections to the IP.

 Model Alert Event Log show repeated connections to the rare IP, filtered with the rarity metric.
Figure 1: Model Alert Event Log show repeated connections to the rare IP, filtered with the rarity metric.
Shows connections to 181.214.147[.]164 and the amount of data transferred.
Figure 2: Shows connections to 181.214.147[.]164 and the amount of data transferred.

On the same day, external connections were observed to the external IP 45.182.189[.]225, along with inbound SSL connections from the same endpoint. OSINT has also linked this IP to the exploitation of Cleo software vulnerabilities [5].

Outgoing connections from a Cleo server to an anomalous endpoint.
Figure 3: Outgoing connections from a Cleo server to an anomalous endpoint.
 Incoming SSL connections from the external IP 45.182.189[.]225.
Figure 4: Incoming SSL connections from the external IP 45.182.189[.]225.

Hours after the last connection to 181.214.147[.]164, the integration detection tool from CrowdStrike, which the customer had integrated with Darktrace, issued an alert. This alert provided additional visibility into host-level processes and highlighted the following command executed on the Cleo server:

“D:\VLTrader\jre\bin\java.exe" -jar cleo.4889

Figure 5: The executed comand “D:\VLTrader\jre\bin\java.exe" -jar cleo.4889 and the Resource Location: \Device\HarddiskVolume3\VLTrader\jre\bin\java.exe.

Three days later, on December 11, another CrowdStrike integration alert was generated, this time following encoded PowerShell command activity on the server. This is consistent with post-exploitation activity where arbitrary PowerShell commands are executed on compromised systems leveraging the default settings of the Autorun directory, as highlighted by Cleo support [6]. According to external researchers , this process initiates connections to an external IP to retrieve JAR files with webshell-like functionality for continued post-exploitation [3]. The IP embedded in both commands observed by Darktrace was 38.180.242[.]122, hosted on ASN 58061(Scalaxy B.V.). There is no OSINT associating this IP with Cleo vulnerability exploitation at the time of writing.

Another device within the same customer network exhibited similar data transfer and command execution activity around the same time, suggesting it had also been compromised through this vulnerability. However, this second device contacted a different external IP, 5.45.74[.]137, hosted on AS 58061 (Scalaxy B.V.).

Like the first device, multiple connections to this IP were detected, with almost 600 MB of data transferred over the SSL protocol.

The Security Integration Detection Model that was triggered  and the PowerShell command observed
Figure 6: The Security Integration Detection Model that was triggered  and the PowerShell command observed
 Incoming connections from the external IP 38.180.242[.]122.
Figure 7: Incoming connections from the external IP 38.180.242[.]122.
Connections to the external IP 5.45.74[.]137.
Figure 8: Connections to the external IP 5.45.74[.]137.
Figure 9: Autonomous Response Actions triggered during the suspicious activities

While investigating potential Cleo servers involved in similar outgoing data activity, Darktrace’s Threat Research team identified two additional instances of likely Cleo vulnerability exploitation used to exfiltrate data outside the network. In those two instances, unusual outgoing data transfers were observed to the IP 176.123.4[.]22 (AS 200019, AlexHost SRL), with around 500 MB of data being exfiltrated over port 443 in one case (the exact volume could not be confirmed in the other instance). This IP was found embedded in encoded PowerShell commands examined by external researchers in the context of Cleo vulnerability exploitation investigations.

Conclusion

Overall, Cleo software represents a critical component of many business operations, being utilized by over 4,000 organizations worldwide. This renders the software an attractive target for threat actors who aim at exploiting internet-facing devices that could be used to compromise the software’s direct users but also other dependent industries resulting in supply chain attacks.

Darktrace / NETWORK was able to capture traffic linked to exploitation of CVE-2024-50623 within models that triggered such as Unusual Activity / Unusual External Data to New Endpoint while its Autonomous Response capability successfully blocked the anomalous connections and exfiltration attempts.

Information on new CVEs, how they're being exploited, and whether they've been patched can be fast-changing, sometimes limited and often confusing. Regardless, Darktrace is able to identify and alert to unusual behavior on these systems, indicating exploitation.

Credit to Maria Geronikolou, Alexandra Sentenac, Emma Fougler, Signe Zaharka and the Darktrace Threat Research team

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Appendices

References

[1] https://blog.httpcs.com/en/file-sharing-and-transfer-software-the-new-target-of-hackers/

[2] https://attackerkb.com/topics/geR0H8dgrE/cve-2024-55956/rapid7-analysis

[3] https://www.huntress.com/blog/threat-advisory-oh-no-cleo-cleo-software-actively-being-exploited-in-the-wild

[4] https://nvd.nist.gov/vuln/detail/CVE-2024-55956

[5] https://arcticwolf.com/resources/blog/cleopatras-shadow-a-mass-exploitation-campaign/

[6] https://support.cleo.com/hc/en-us/articles/28408134019735-Cleo-Product-Security-Advisory-CVE-Pending

[7] https://support.cleo.com/hc/en-us/articles/360034260293-Local-HTTP-Users-Configuration

Darktrace Model Alerts

Anomalous Connection / Data Sent to Rare Domain

Unusual Activity / Unusual External Data to New Endpoint

Unusual Activity / Unusual External Data Transfer

Device / Internet Facing Device with High Priority Alert

Anomalous Server Activity / Rare External from Server

Anomalous Connection / New User Agent to IP Without Hostname

Security Integration / High Severity Integration Incident

Security Integration / Low Severity Integration Detection

Autonomous Response Model Detections

Antigena / Network / Insider Threat / Antigena Large Data Volume Outbound Block

Antigena / Network / Significant Anomaly / Antigena Significant Server Anomaly Block

Antigena / Network / Significant Anomaly / Antigena Controlled and Model Alert

Cyber AI Analyst Incidents

Unusual External Data Transfer

MITRE ATT&CK Mapping

Tactic – Technique

INITIAL ACCESS – Exploit Public-Facing Application

COMMAND AND CONTROL – Application Layer Protocol (Web Protocols)

COMMAND AND CONTROL – Encrypted Channel

PERSISTENCE – Web Shell

EXFILTRATION - Exfiltration Over C2 Channel

IoC List

IoC       Type    Description + Probability

181.214.147[.]164      IP Address       Likely C2 Infrastructure

176.123.4[.]22            IP Address       Likely C2 Infrastructure

5.45.74[.]137               IP Address           Possible C2 Infrastructure

38.180.242[.]122        IP Address       Possible C2 Infrastructure

Get the latest insights on emerging cyber threats

Attackers are adapting, are you ready? This report explores the latest trends shaping the cybersecurity landscape and what defenders need to know.

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
Maria Geronikolou
Cyber Analyst

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May 28, 2026

From Efficiency to Exposure: How AI Adoption Is Creating Unseen Vulnerabilities on the Factory Floor

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How AI agents impact the manufacturing industry

Security teams and IT personnel across the manufacturing industry are under constant pressure to protect production, maintain uptime, and safeguard critical assets but the rise of AI is bringing huge new opportunities alongside new cyber risks. Across manufacturing, AI is embedded into workflows, decision-making, and increasingly, autonomous AI agents are acting on behalf of employees and systems.  

Agentic systems are powerful because they can act independently, but that same autonomy also creates cyber and operational risk. Agents have extensive permissions and are capable of carrying out complex tasks, making decisions, and interacting with tools or external systems with little to no human intervention.

Unlike traditional AI models that perform predefined tasks, AI agents use advanced techniques to mimic human decision-making processes, dynamically adapting to new challenges, making decision and taking action based on their own judgement. They look like employees operationally but lack judgment, ethics, or fear of consequences like humans do. This means they can be easily manipulated by cybercriminals, and an AI agent embedded across an OT network creates threats that extend well beyond data exposure. For example, at BMW, AI identifies faults in welding processes as they occur. At its Spartanburg plant, AI monitors the weld of 300-400 metal studs onto every SUV frame to detect misplaced or faulty studs and correct them instantly. Corruption of BMW’s AI system could lead to catastrophic quality control errors.

Adopting agentic AI systems across manufacturing raises some concerns across security teams. New data from our State of AI Cybersecurity survey shows that 78% of manufacturing security professionals are worried about employee use of AI agents – their top concern. That’s followed by employee use of generative AI tools like CoPilot and ChatGPT, a worry for 76% of security professionals at manufacturing organizations. As these tools gain more access to business data and processes, and more autonomy within organizations, security teams, who today have minimal visibility of agent activity in their environments, increasingly have sensitive data exposure (a worry for 60%) and accidental policy and regulatory violations (59%) on their minds.

External AI-powered threats are evolving just as quickly

The same capabilities transforming manufacturing are also reshaping cyberattacks.

AI is enabling attackers to automate reconnaissance, refine targeting, and adapt in real time. What once required time and manual effort can now be executed continuously and at scale. Manufacturers are already seeing the impact. According to manufacturing security professionals we surveyed, 76% are already being impacted by AI-powered threats and 90% see AI increasing the success of social engineering attacks.

And the techniques themselves are evolving. Concerns across the manufacturing sector show growing anxiety about the range of AI-powered attack routes, most pressingly of adaptive malware that evolves in real-time – a prospect half (49%) of manufacturing security professionals we surveyed are worried by, a full 9% more than the average across industries. AI adaptive malware is followed by:

  • Automated vulnerability scanning and exploit chaining (48%) which has become even more pressing as Anthropic’s new Mythos AI Model supercharges vulnerability discovery
  • Hyper-personalized phishing campaigns (46%), which remain a mainstay in hackers’ arsenals, and AI has amplified their effectiveness by making phishing emails more convincing and harder to detect.

This is not just an increase in volume, it is a shift toward threats that evolve as they unfold - often faster than static defenses can respond.

Despite rising awareness, many manufacturers are not yet equipped to manage this shift. More than half (51%) say they are not adequately prepared for AI-driven threats, and only 37% have formal policies governing AI deployment.  

Securing AI through visibility, context, and guardrails

Addressing this challenge does not require manufacturers to slow innovation. It requires a different approach to security, one that can operate at the same speed and scale as AI. Three specific priorities are emerging for manufacturers looking to take advantage of the power of AI.

Visibility is foundational.  

Organizations need to understand where AI is being used, what it can access, and how it behaves across both IT and OT environments. Without that, risk cannot be measured or managed. It is no surprise that Darktrace’s research found that 91% of manufacturing security professionals said that they need to understand how AI makes decisions before trusting it. This is even more critical in operational settings where disruption has safety, environmental, financial, and reputational impacts.

Context is what turns visibility into action.  

In environments shaped by AI, normal behavior is constantly shifting. Detecting threats requires a behavioral approach; understanding patterns of life across the organization and identifying subtle deviations in real time – a step change in organizations’ traditional approach to security and risk management.

Guardrails ensure that agency does not become exposure  

As AI systems take on greater responsibility, organizations need clear boundaries around what they can do and when they can act independently. These controls must be embedded into systems themselves, not applied after the fact.  

Securing AI Agents Across Manufacturing IT and OT

The rise of agentic AI is transforming manufacturing - powering next-generation operations while reshaping the security landscape. This is not just an increase in threats, but a shift to autonomous systems, continuously evolving behaviors, and risks moving at machine speed. For organizations trying to grapple with the challenge of enabling AI while managing the risk, visibility, context and guardrails should be foundational.

Darktrace helps manufacturers build secure AI approaches by making those foundations possible. It provides visibility and real-time detection and response to unusual activity across IT and OT environments and allows organizations to understand AI activity from the prompts employees use and the agents they build to how those agents are behaving across the environment. For manufacturers scaling AI, this delivers a foundation for innovation without sacrificing control.

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About the author
Oakley Cox
Director of Product

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May 28, 2026

How to Evaluate AI Vendors: 5 Key categories for AI Adoption

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Understanding the AI buyers’ market

AI adoption has become a central topic of discussion in boardrooms, drawing growing interest from business leaders. Ultimately, organizations hope that an investment in AI technology will have tremendous returns. However, the process of buying an AI solution is not as straight forward as it appears on the surface.  

While business leaders may be eager to improve productivity across their operations, practitioners responsible for evaluating and selecting AI solutions may not always have the visibility or technical understanding needed to make the right decisions for their business. What is typically marketed as a holistic solution to their most critical problems is usually followed by uncertainty when AI tools are finally operationalized in real environments.

This guide is intended to support security leaders who are under growing pressure to adopt AI tools while navigating complex terminology, vendor claims, and increasingly crowded buying cycles. Ultimately, the goal is to help organizations evaluate and adopt AI in a safe, effective, and well-governed way. To support this, we’ve structured the evaluation framework across five key categories:

  1. Governance, safety, and data controls
  1. Data gathering and training
  1. Model and technique choice
  1. Performance and accuracy validation    
  1. Interpretability, adjustability, and transparency    

What buying AI looks like in cybersecurity

While investing in AI can bring immense benefits to your security team, first-time buyers of AI cybersecurity solutions may not know where to start. They will have to determine the type of tool they want, know the options available, and evaluate vendors. Research and understanding are critical to ensure purchases are worth the investment.  

With acceleration in AI adoption, accompanied by the recent boom in agentic AI and autonomous agents, CISOs must look “beneath the hood" of these tools to understand how they work, how they are governed, and to ensure the system is secure and compliant with internal policies.

Challenges in the AI buyers’ marketplace  

The AI security software market is buzzing with hype and flashy promises, which, understandably, needs to be addressed with due diligence. Potential buyers, especially in the cybersecurity space, are hesitant when it comes to allowing AI autonomous capabilities across their workflows, and a lack of vendor transparency can exacerbate those feelings.  

Reinforcing this sentiment, research from this year's Darktrace’s State of AI Cybersecurity report shows where confidence and hesitancy emerge amongst potential buyers. On the one hand, security professionals agree that they have good visibility into the logic and reasoning processes their AI solutions use. However, they lack the explainability and trust to allow AI to take independent remedial action.

  • 89% say they have good visibility into the reasoning behind the outputs generated by AI solutions
  • 92% say they need to understand how a defensive AI tool makes decisions before they can trust it
  • Only 14% say they allow AI to act independently, performing autonomous actions without human approval
  • 74% say they are limiting the autonomy of AI taking action in their SOC until explainability improves

Given the desire for trust and explainability we are seeing from buyers, it's important for them to be equipped with the right questions to ask vendors during an assessment or POV of AI tools in order to demystify marketing hype from real operational outcomes.

Below is a list of categories in which buyers can assess AI vendors or AI Service Providers (AISPs) to help reach safe adoption and maximize their ROI.  

5 categories of AI vendor assessment

Darktrace groups these AI-related questions into 5 categories: governance, data and training, model and technique choice, performance validation, and interpretability and adjustability. By asking questions regarding each of these 5 categories, buyers can gain a deeper understanding of how an AISP’s systems work and whether they suit their business requirements.

Governance, safety, and data controls

Governance of AI systems is critical for all AISPs. Whether their platform is based around a single model, or is a more complex, composite AI solution, strong governance is essential to ensure the system is safe, robust, and reliable.

A simple question you could ask is:

What AI governance policies and frameworks do you follow, and/or certifications do you currently maintain?

For more questions you can ask vendors, download the full guide here.

Darktrace is certified to the ISO/IEC 42001 standard, the world’s first AI Management System (AIMS) standard. ISO/IEC 42001 addresses the unique ethical and technical challenges AI poses by setting out a structured way to manage risks such as transparency, accuracy, and misuse. This includes a commitment to ethical AI development, and effective management and monitoring of AI systems both prior to and continually after release.

Data gathering and training

Accurate, meaningful, and unbiased data gathering is the first important step in producing any AI system. An AI model trained using inaccurate, unbalanced, or poor-quality training data will fail to perform optimally.

To alleviate concerns regarding training data quality, a question you could ask is:

What steps do you take to prevent bias in your AI models and training data?

For more questions, download the full guide here.

AISPs should be able to provide information about the steps taken, workflows followed, and auditing performed to reduce AI bias where appropriate. While it’s sometimes impossible to fully remove bias from an AI model, appropriate actions should be taken to mitigate or reduce bias where relevant.

Model and technique choice

Different AI techniques are optimal for different tasks. For example, research from Gartner suggests that relying on a single “one-size-fits-all" model can lead to data gaps, especially in highly specialized domains.

To achieve more accurate and robust AI solutions, AI leaders should move beyond using just one model or technique, embrace composite AI practices, and adopt a holistic AI system perspective.

A straightforward question you could ask is simply:

What type(s) of AI model(s) do you utilize in your solution?

For more questions, download the full guide here.

While specific detailed information about custom systems used by AISPs is likely proprietary, buyers should expect vendors to be able to provide an overview of the broad techniques used. This will allow you as a buyer to determine if the type of model is appropriate for your use case.

Performance and accuracy validation  

Testing and evaluation of performance is essential for all AI systems. Performance analysis should be performed both before release and continually after release to identify potential data or model drift.  

A question you could ask to understand an AISPs testing workflow is:

How do you audit, test, evaluate, verify, and validate your AI model outputs?

For more questions, download the full guide here.

Testing workflows will likely vary depending on the type of model – measurements relevant to one system may not always be relevant to others. Assessment of systems should also extend beyond these standard accuracy and robustness tests, and should also feature physical performance, such as latency and resource consumption.  

Interpretability, adjustability, and transparency  

AI systems are typically a black box, simply providing an output without an explanation of how that output was attained. Interpretability and transparency are critical to ensure that both SOC teams and end-users trust the outputs of a system to be accurate and meaningful.

A question you could ask is:

How do you promote a trust relationship between human analysts and AI outputs?

For more questions, download the full guide here.

In the context of cybersecurity, trust and interpretability are even more essential. This is particularly relevant for generative AI-based systems (including most AI Agents), where the risk of hallucination can reduce trust in responses.

Cybersecurity systems often need to perform autonomous actions to block incoming threats – an email filtering system may hold potentially dangerous emails; a firewall may block malicious inbound connections. If SOC teams can’t trust these systems to perform accurately, these systems may be limited or disabled, critically reducing their defensive power.

Darktrace as an AI-native cybersecurity vendor

Darktrace has been building and applying AI in cybersecurity for over a decade, developing its capabilities alongside an increasingly complex and fast‑moving threat landscape. This experience has resulted in a mature, multi-layered approach to AI, which continuously learns the normal patterns of each organization to understand behavior, interpret context, and identify meaningful deviations — without relying on predefined rules or known attack signatures. Over time, this has enabled a proven behavioral understanding that helps uncover subtle signals of risk that may otherwise be missed.

With the backing of our ISO/IEC 42001 certification, stakeholders, customers, and partners can be confident that Darktrace is responsibly, ethically, and safely developing its AI systems, and managing the use of AI in day-to-day operations in a compliant and secure manner.  

Explore the principles behind Darktrace’s responsible AI approach, informed by collaboration with global experts in academia and governments, detailing how accountability, explainability, and continuous validation are built into its cybersecurity technology.

How Darktrace secures AI systems

Darktrace now brings these capabilities to monitor and respond to risk generated from AI systems across organizations with Darktrace / SECURE AI. This solution analyzes how prompts, agents, and systems are used within the context of each organization, bringing every AI interaction into a single view. This unique approach helps teams understand intent, assess risk, protect sensitive data, and enforce policy across both human and AI agent activity.

Stay up to date

Sign up for the Secure AI Readiness Program here: This gives you exclusive access to the latest news on the latest AI threats, updates on emerging approaches shaping AI security, and insights into the latest innovations, including Darktrace’s ongoing work in this area.

Ready to talk with a Darktrace expert on securing AI? Register here to receive practical guidance on the AI risks that matter most to your business, paired with clarity on where to focus first across governance, visibility, risk reduction, and long-term readiness.  

Further Reading on AI in cybersecurity

When deciding to invest in an AI solution, it’s important to understand what this means for you and your organization. The questions presented here are only a starting point in understanding an AI solution and whether it is appropriate for your use case.  

Gain deeper knowledge on applications of AI in cybersecurity and Darktrace’s multi-layered AI in the AI Arsenal White Paper.

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About the author
Jamie Bali
Technical Author (AI) Developer
Your data. Our AI.
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