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April 15, 2021

AI Neutralizes Hafnium Cyber Attack in December 2020

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Apr 2021
Protect your business from cyber attacks with AI technology. Learn how Darktrace neutralized the Hafnium attack against Exchange servers in December 2020.

In early December 2020, Darktrace AI autonomously detected and investigated a sophisticated cyber-attack that targeted a customer’s Exchange server. On March 2, 2021, Microsoft disclosed an ongoing campaign by the Hafnium threat actor group leveraging Exchange server zero-days.

Based on similarities in techniques, tools and procedures (TTPs) observed, Darktrace has now assessed with high confidence that the attack in December was the work of the Hafnium group. Although it is not possible to determine whether this attack leveraged the same Exchange zero-days as reported by Microsoft, the finding suggests that Hafnium’s campaign was active several months earlier than assumed.

As a result, organizations may want to go back as far as early December 2020 to check security logs and tools for signs of initial intrusion into their Internet-facing Exchange servers.

As Darktrace does not rely on rules or signatures, it doesn’t require a constant cloud connection. Most customers therefore operate our technology themselves, and we don’t centrally monitor their detections.

At the time of detection in December, this was one of many uncategorized, sophisticated intrusions that affected only a single customer, and was not indicative of a broader campaign.

This means that while we protect our customers from individual intrusions, we are not in a position to do global campaign tracking like other companies which focus primarily on threat intelligence and threat actor tracking.

In this blog, we will analyze the attack to aid organizations in their ongoing investigations, and to raise awareness that the Hafnium campaign may have been active for longer than previously disclosed.

Overview of the Exchange attack

The intrusion was detected at an organization in the critical national infrastructure sector in South Asia. One hypothesis is that the Hafnium group was testing out and refining its TTPs, potentially including the Exchange server exploit, before running a broad-scale campaign against Western organizations in early 2021.

The threat actor used many of the same techniques that were observed in the later Hafnium attacks, including the deployment of the low-activity China Chopper web shell, quickly followed by post-exploitation activity – attempting to move laterally and spread to critical devices in the network.

The following analysis demonstrates how Darktrace’s Enterprise Immune System detected the malicious activity, how Cyber AI Analyst automatically investigated on the incident and surfaced the alert as a top priority, and how Darktrace RESPOND (formerly known as 'Antigena') would have responded autonomously to shut down the attack, had it been in active mode.

All the activity took place in early December 2020, almost three months before Microsoft released information about the Hafnium campaign.

Figure 1: Timeline of the attack from early December 2020

Initial compromise

Unfortunately, the victim organization did not keep any logs or forensic artefacts from their Exchange server in December 2020, which would have allowed Darktrace to ascertain the exploit of the zero-day. However, there is circumstantial evidence suggesting that these Exchange server vulnerabilities were abused.

Darktrace observed no signs of compromise or change in behavior from the Internet-facing Exchange server – no prior internal admin connections, no broad-scale brute-force attempts, no account takeovers, no malware copied to the server via internal channels – until all of a sudden, it began to scan the internal network.

While this is not conclusive evidence that no other avenue of initial intrusion was present, the change in behavior on an administrative level points to a complete takeover of the Exchange server, rather than the compromise of a single Outlook Web Application account.

To conduct a network scan from an Exchange server, a highly privileged, operating SYSTEM-level account is required. The patch level of the Exchange server at the time of compromise appears to have been up-to-date, at least not offering a threat actor the ability to target a known vulnerability to instantly get SYSTEM-level privileges.

For this reason, Darktrace has inferred that the Exchange server zero-days that became public in early March 2021 were possibly being used in this attack observed in early December 2020.

Internal reconnaissance

As soon as the attackers gained access via the web shell, they used the Exchange server to scan all IPs in a single subnet on ports 80, 135, 445, 8080.

This particular Exchange server had never made such a large number of new failed internal connections to that specific subnet on those key ports. As a result, Darktrace instantly alerted on the anomalous behavior, which was indicative of a network scan.

Autonomous Response

Darktrace RESPOND was in passive mode in the environment, so was not able to take action. In active mode, it would have responded by enforcing the previously learned, normal ‘pattern of life’ of the Exchange server – allowing the server to continue normal business operations (sending and receiving emails) but preventing the network scan and any subsequent activity. These actions would have been carried out via various integrations with the customer’s existing security stack, including Firewalls and Network Access Controls.

Specifically, when the network scanning started, the ‘Antigena Network Scan Block’ was triggered. This means that for several hours, Darktrace RESPOND (Antigena) would have blocked any new outgoing connections from the Exchange server to the scanned subnet on port 80, 135, 445, or 8080, preventing the infected Exchange server from conducting network scanning.

As a result, the attackers would not have been able to conclude anything from their reconnaissance — all their scanning would have returned closed ports. At this point, they would need to stop their attack or resort to other means, likely triggering further detections and further Autonomous Response.

The network scan was the first step touching the internal network. This is therefore a clear case of how Darktrace RESPOND can intercept an attack in seconds, acting at the earliest possible evidence of the intrusion.

Lateral movement

Less than an hour after the internal network scan, the compromised Exchange server was observed writing further web shells to other Exchange servers via internal SMB. Darktrace alerted on this as the initially compromised Exchange server had never accessed the other Exchange servers in this fashion over SMB, let alone writing .aspx files to Program Files remotely.

A single click allowed the security team to pivot from the alert into Darktrace’s Advanced Search, revealing further details about the written files. The full file path for the newly deployed web shells was:

Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\owa\auth\Current\themes\errorFS.aspx

The attackers thus used internal SMB to compromise further Exchange servers and deploy more web shells, rather than using the Exchange zero-day exploit again to achieve the same goal. The reason for this is clear: exploits can often be unstable, and an adversary would not want to show their hand unnecessarily if it could be avoided.

While the China Chopper web shell has been deployed with many different names in the past, the file path and file name of the actual .aspx web shell bear very close resemblance to the Hafnium campaign details published by Microsoft and others in March 2021.

As threat actors often reuse naming conventions / TTPs in coherent campaigns, it again indicates that this particular attack was in some way part of the broader campaign observed in early 2021.

Further lateral movement

Minutes later, the attacker conducted further lateral movement by making more SMB drive writes to Domain Controllers. This time the attackers did not upload web shells, but malware, in the form of executables and Windows .bat files.

Darktrace alerted the security team as it was extremely unusual for the Exchange server and its peer group to make SMB drive writes to hidden shares to a Domain Controller, particularly using executables and batch files. The activity was presented to the team in the form of a high-confidence alert such as the anonymized example below.

Figure 2: Example graphic of Darktrace detecting unusual connectivity

The batch file was called ‘a.bat’. At this point, the security team could have created a packet capture for the a.bat file in Darktrace with the click of a button, inspecting the content and details of that script at the time of the intrusion.

Darktrace also listed the credentials involved in the activity, providing context into the compromised accounts. This allows an analyst to pivot rapidly around the data and further understand the scope of the intrusion.

Bird’s-eye perspective

In addition to detecting the malicious activity outlined above, Darktrace’s Cyber AI Analyst autonomously summarized the incident and reported on it, outlining the internal reconnaissance and lateral movement activity in a single, cohesive incident.

The organization has several thousand devices covered by Darktrace’s Enterprise Immune System. Nevertheless, over the period of one week, the Hafnium intrusion was in the top five incidents highlighted in Cyber AI Analyst. Even a small or resource-stretched security team, with only a few minutes available per week to review the highest-severity incidents, could have seen and inspected this threat.

Below is a graphic showing a similar Cyber AI Analyst incident created by Darktrace.

Figure 3: A Cyber AI Analyst report showing unusual SMB activity

How to stop a zero-day

Large scale campaigns which target Internet-facing infrastructure and leverage zero-day exploits will continue to occur regularly, and such attacks will always succeed in evading signature-based detection. However, organizations are not helpless against the next high-profile zero-day or supply chain attack.

Detecting the movements of attackers inside a system and responding to contain in-progress threats is possible before IoCs have been provided. The methods of detection outlined above protected the company against this attack in December, and the same techniques will continue to protect the company against unknown threats in the future.

Learn more about how Darktrace AI has stopped Hafnium cyber-attacks and similar threat actors

Darktrace model detections:

  • Device / New or Uncommon WMI Activity
  • Executable Uploaded to DC
  • Compliance / High Priority Compliance Model Breach
  • Compliance / SMB Drive Write
  • Antigena / Network / Insider Threat / Antigena Network Scan Block
  • Device / Network Scan - Low Anomaly Score
  • Unusual Activity / Unusual Internal Connections

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.
Author
Max Heinemeyer
Chief Product Officer

Max is a cyber security expert with over a decade of experience in the field, specializing in a wide range of areas such as Penetration Testing, Red-Teaming, SIEM and SOC consulting and hunting Advanced Persistent Threat (APT) groups. At Darktrace, Max is closely involved with Darktrace’s strategic customers & prospects. He works with the R&D team at Darktrace, shaping research into new AI innovations and their various defensive and offensive applications. Max’s insights are regularly featured in international media outlets such as the BBC, Forbes and WIRED. Max holds an MSc from the University of Duisburg-Essen and a BSc from the Cooperative State University Stuttgart in International Business Information Systems.

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December 12, 2024

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Company Shuts Down Cyber-attacks with “Flawless” Detection and Response from Darktrace

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Growing pains: Balancing efficiency with risk  

This organization has recently scaled its operations, and numerous acquisitions have significantly boosted the organization’s capabilities and growth. However, this also creates work and high expectations for the organization’s IT and security teams. Within 12 months of an acquisition, the teams must fully integrate each new business onto the company’s platform. “A huge piece of that integration plan is rolling out our security controls,” said the CISO. “While our goal is to connect those facilities up as quickly as possible to drive efficiency, we also need to implement the proper security controls to protect the enterprise.”

Gap beyond the perimeter  

The organization had established strong security measures to safeguard its perimeter; however, the CISO identified a critical gap in real-time network monitoring. If the perimeter were breached, threats were only discovered after an endpoint was compromised and the issue was manually reported.

As digital transformation progresses, the need to adopt advanced technologies is becoming essential, particularly as organizations begin to open up operational environments to greater connectivity. Many processes still rely on traditional methods, and integrating innovative solutions could drive significant improvements in efficiency and productivity. “We’re committed to adopting cutting-edge technologies,” the CISO explained. “But we understood that without more robust network security controls, opening up our operational environments would expose us to heightened risks, including advanced threats like ransomware.”

Building a layered, proactive security strategy with Darktrace  

To close the gap beyond the perimeter, the company embarked on a free trial with Darktrace. The CISO recalls: “The trials were fantastic. It was obvious that Darktrace was exactly what we needed. The Darktrace team was also very knowledgeable and helpful throughout the process, which was impressive.”  

Today, the organization is using a combination of Darktrace solutions for its layered security approach, including:

Detecting unusual behavior with AI  

Darktrace’s use of machine learning and Self-Learning AI is one of the reasons the company chose Darktrace. Instead of teaching an AI system what an ‘attack’ looks like, training it on large data lakes of thousands of organizations’ data, Darktrace AI learns from the company’s own unique data and user activity to learn and create baseline models of what ‘normal’ looks like for their business.

Darktrace can then detect subtle deviations and unusual activity that signals a possible threat. “That fascinated us because what it really means is this technology doesn’t need to know about every single threat because the threat itself isn’t important, it’s the behavior of the activity that’s important. That capability is unique when it when it comes to threat detection,” said the CISO.

Identifying and mitigating high-impact attack paths

The security team appreciated that with Darktrace they could take a more proactive approach to security by exposing high-risk attack paths through modeling and AI risk assessments. Darktrace / Proactive Exposure Management gives them visibility into vulnerable entry points and assets, identifies active risks, and prioritizes the most important security issues to be addressed.

“Specific users and assets within our business have a higher risk of being targeted by a cyber-attack, for example our executives,” said the CISO. “With Darktrace, we get an adversarial view of our risk. We can see the attack path around those potential targets and proactively take measures to mitigate that vulnerability and prevent an attack.”

Driving up productivity while putting the brakes on cyber-attacks  

The security team collaborated with Darktrace to fine tune the models that really fit their business. With Darktrace now automating most of their threat detection and response efforts, productivity has soared, the security team is now focused on delivering greater value to the business and, most importantly, Darktrace proved it could quickly detect and shut down a major cyber-attack–and do so without impacting business operations.

Fueling team productivity with automation and AI

Prior to using Darktrace, the security team had little visibility into potential risks beyond the perimeter. Today, the team has full control and visibility over the network. “My team is now spending 80-90% of their time doing proactive work because Darktrace is managing the vast majority of our detect and response needs. The team really has faith in the Darktrace system,” said the CISO.  

With less time spent on low-level manual tasks, the security team can now focus on higher priority initiatives. For example, they have expanded their internal vulnerability assessments across the entire group. The team couldn’t focus on this additional audit and vulnerability management work if Darktrace wasn’t taking care of most of their security monitoring. “Darktrace has allowed us to move on to these additional kinds of governance projects that we otherwise would have to hire an army of staff to get through”.

Stopping email threats in their tracks

Using Darktrace / EMAIL, the company has identified and blocked a significant percentage of emails that were making it past their native email filters. “Darktrace is especially good at detecting impersonation emails, and we really appreciate its ability to automatically remove suspicious emails directly from a user’s inbox. It adds an extra level of confidence,” said the CISO.

Self-Learning AI understands anomalies within unique communication patterns to stop known and unknown threats. For example, when an employee sent an email to a brand new domain, Darktrace identified the behavior as unusual and inconsistent with baseline models and blocked the email.

Darktrace passes the biggest test of all

In 2024, the company experienced the value of the security system firsthand when attackers exploited a vulnerability in a third-party remote support solution that they was using. This solution provided remote access and tech support capabilities. If successful, the attackers could have infiltrated high-value end points and created their own administrative user, giving them full control over the server.

“We first became aware of the attack when Darktrace notified us of unusual behavior coming from the remote support server,” said the CISO. The attackers were attempting to put backdoors onto the service with the intent of selling access to the highest bidder who would then install ransomware on their servers. It all happened very quickly, as the attackers tried to connect to the internal network and other servers, while also firing off a host of other actions, like PowerShell commands, to escalate their privileges.  

“Darktrace worked flawlessly. There was no chance that ransomware was ever going to come in,” the CISO said. “Even though there was no signature to really look at, Darktrace realized this was not normal behavior for this server, shutting down connections and doing everything it could do to stop the attack.” Within eight hours, the security team identified and stopped the attack, severed its connection to the third-party solution, and completed additional analysis and clean-up. “In addition to our own investigation, third parties like our external SOC and legal department also confirmed that Darktrace performed as expected. We were able to report back to the executive team that there was zero risk that any data or systems were compromised.”

Post-attack, there was no need to make any changes to Darktrace. The team consistently reviews its models and baselines, often collaborating with Darktrace to make adjustments when needed to continuously improve performance. “Because of this relationship and constant engagement with Darktrace’s technical teams, we didn't have to go back and ask: ‘why wasn’t this updated’ or ‘why didn’t this model work.’ The models worked.”

His advice to other organizations facing similar challenges? First, focus on updating, patching, and vulnerability management, and act quickly when vulnerabilities are identified. His second piece of advice: “have an automated detection system like Darktrace in place so you can respond at the speed that these attacks evolve. Humans can no longer keep up with a scripted attack as it moves around and tries to compromise items on your network. You need the right technology to fight these types of attacks.”

Dynamic capabilities for a dynamic future

Real-time playbooks

With a proactive, enterprise-wide security strategy in place, the CISO now has the time to think about future projects and innovations. He’s particularly interested in the idea of generating playbooks on the fly in response to real-time events. He believes cyber-attacks are far too varied for a static playbook to be useful; when an attack strikes, teams need to quickly understand exactly what’s in front of them and how to shut it down. “This fits into our future cybersecurity strategy, and Darktrace is the only company I’ve seen talking about building playbooks dynamically. This kind of technology would really help bring our cybersecurity strategy full circle.”

“Darktrace ’s technology, experience and expertise is helping us staying ahead of cyber-attacks, minimizing our risk and driving greater productivity for our team,” said the CISO. In collaboration with Darktrace, the team have created a security foundation that is both powerful and agile. “While Darktrace is detecting and responding to attacks targeting our business today, we know that it’s always learning, adapting and scaling to ensure we’re protected tomorrow. That gives me peace of mind and the freedom to focus on our future.”

Download the Darktrace / NETWORK Solution Brief

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Protect in real time: Defend against known and emerging threats without relying on historical data or external intelligence.

Full visibility: Gain comprehensive insights across all network environments, including on-premises, cloud, and remote devices.

AI-powered efficiency: Streamline incident response with AI automation, saving time and resources while ensuring minimal disruption to operations.

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Darktrace is Positioned as a Leader in the IDC MarketScape: Worldwide Network Detection and Response 2024 Vendor Assessment

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Darktrace is pleased to announce that we have been positioned as a Leader in the IDC MarketScape: Worldwide Network Detection and Response 2024 Vendor Assessment. We believe this further highlights Darktrace’s position as a pioneer in the NDR market and follows similar recognition from KuppingerCole, who recently named Darktrace as an Overall Leader, Product Leader, Market Leader and Innovation Leader in the KuppingerCole Leadership Compass: Network Detection and Response (2024).

Network Detection and Response (NDR) solutions are uniquely positioned to provide visibility over the core hub of a business and employee activity, analyzing North-South and East-West traffic to identify threats across the modern network. NDR provides a rich and true source of anomalies and goes beyond process level data that is relied on by Endpoint Detection and Response (EDR) agents that do not provide network level visibility and can be misconfigured at any time.1

Metadata from network traffic can be used to detect a variety of different threats based on events such as anomalous port usage, unusual upload/download activity, impossible travel and many other activities. This has been accelerated by the increased usage of user behavioral analytics (UBA) in network security, which establishes statistical baselines about network entities and highlights deviations from expected activity.1

Darktrace is recognized as a Leader in the IDC MarketScape due to our leadership in the market and our pioneering leadership in AI over the past decade, alongside a variety of other unique differentiators and innovations in the NDR industry.

Darktrace / NETWORK™ delivers full visibility, real time threat detection and Autonomous Response capabilities across an organization’s on-premises, cloud, hybrid and virtual environments, including remote worker endpoints.

Unique Approach to AI

Most NDR vendors and network security tools such as IDS/IPS rely on detecting known attacks with historical data and supervised machine learning, leaving organizations blind and vulnerable to novel threats such as zero-days, variants of known attacks, supply chain attacks and insider threats.

These vendors also tend to apply AI models that are trained globally, and are not unique to each organization’s environment, which creates a high number of false positives and alerts that ultimately lack business context.

The IDC MarketScape recognizes that Darktrace takes a differentiated approach in the market with regards to delivering network detection and response capabilities, noting; “Darktrace is unique in that it does not rely on rules and signatures but rather learns what constitutes as normal for an organization and generates alerts when there is a deviation.”1

Darktrace / NETWORK achieves this through the use of Self-Learning AI and unsupervised machine learning to understand what is normal network behavior, continuously analyzing, mapping and modeling every connection to create a full picture of devices, identities, connections and potential attack paths. Darktrace Self-Learning AI autonomously optimizes itself to cut through the noise and quickly surface genuine, prioritized network security incidents – significantly reducing false positives and removing the hassle of needing to continually tuning alerts manually.

Darktrace’s unique approach to AI also extends to the investigation and triage of network alerts with Cyber AI Analyst. Unlike a chat or prompt based LLM, Cyber AI Analyst investigates all relevant alerts in an environment, including third party alerts, autonomously forming hypotheses and reaching conclusions just like a human analyst would, accelerating SOC Level 2 analyses of incidents by 10x. Cyber AI Analyst also typically providing SOC teams with up to 50,000 additional hours annually of Level 2 analysis producing high level alerts and written reporting, transforming security operations.2

Darktrace also uses its deep understanding of what is normal for a network to identify suspicious behavior, leveraging Autonomous Response capabilities to shut down both known and novel threats in real time, taking targeted actions without disrupting business operations. Darktrace / NETWORK is the only NDR solution that can autonomously enforce a pattern of life based on what is normal for a standalone device or group of peers, rapidly containing and disarming threats based on the overall context of the environment and a granular understanding of what is normal for a device or user – instead of relying on historical attack data.

Continued NDR Market Leadership

Darktrace has been recognized as a Leader in the NDR market, and the IDC MarketScape listed a variety of strengths:

  • Darktrace achieves roughly one-fifth of all global NDR revenue. This is important because other IT and cybersecurity solutions providers necessarily want to have integration with Darktrace.
  • The AI algorithms that Darktrace uses for NDR have had 10 years of deployments, tuning, and learning to draw from.
  • Darktrace is available as a SaaS, as an enterprise license, and as physical, hybrid, or virtual appliances. Darktrace also offers an endpoint agent and visibility into VPN and ZTNA.
  • Darktrace integrates with 30+ different interfaces including SIEM, SOAR, XDR platforms, IT ticketing solutions, and their own dashboards. The Darktrace Threat Visualizer highlights events and incidents from the entire deployment including cloud, apps, email, endpoint, zero trust, network, and OT.
  • Darktrace / NETWORK charts the progress that the SOC is making over time with key metrics such as MTTD/MTTR, alerts generated and processed, and other criteria.
  • Darktrace reported coverage of 14 MITRE ATT&CK categories, 158 techniques, and 184 subtechniques

Proactive Network Resilience

The IDC MarketScape notes, “Ultimately, NDR shines as a standalone detection and response technology but is especially powerful when combined with other platforms. NDR in combination with other control points such as endpoint, data, identity, and application provides the proper context when winnowing alerts and trying to uncover a single source of truth.” . Darktrace comprehensively addresses this as part of the ActiveAI Security Platform, by combining network alerts with data from / EMAIL, / IDENTITY, / ENDPOINT, / CLOUD and / OT, providing deeper contextual analysis for each network alert and automatically enriching investigations.

Darktrace also goes beyond NDR solutions with capabilities that are closely linked to our NDR offering, helping clients to achieve and maintain a state of proactive network resilience:

  • Darktrace / Proactive Exposure Management – look beyond just CVE risks to discover, prioritize and validate risks by business impact and how to address them early, reducing the number of real threats that security teams need to handle.
  • Darktrace / Incident Readiness & Recovery – lets teams respond in the best way to each incident and proactively test their familiarity and effectiveness of IR workflows with sophisticated incident simulations based on their own analysts and assets.

Together, these solutions allow Darktrace / NETWORK to go beyond the traditional approach to NDR and shift teams to a more hardened and proactive stance.

Protecting Clients with Continued Innovation

Darktrace invests heavily in Research and Development to continue providing customers with market-leading NDR capabilities and innovations, which was reflected in our position in the Leader category of the MarketScape report for both capabilities and strategy. We are led by the needs and challenges of our customers, which serve as the driving force behind our continued innovation and leadership in the NDR market. The IDC MarketScape report underlines this approach with the following feedback presented by Darktrace customers:

“A customer intimated that 99% of their detections were OOTB with little need to tune or define parameters.”
“A customer reported that it had early warnings for adversarial tactics such as suspicious SMB scanning, suspicious remote execution, remote desktop protocol (RDP) scanning, data exfiltration, C2C, LDAP query, and suspicious Kerberos activity.”
“The client could use Regex to determine if suspicious behavior was found elsewhere on the network.”

Thousands of customers around the world across all industries and sectors rely on Darktrace / NETWORK to protect against known and novel threats. From the latest vulnerabilities in network hardware to sophisticated new strains of ransomware and everything in-between, Darktrace helps clients detect and respond to all types of threats affecting their networks and avoid business disruption, even from the latest attacks.

Find out more about the unique capabilities of Darktrace / NETWORK and our application of AI in network security in the IDC MarketScape excerpt.

References

  1. IDC MarketScape: Worldwide Network Detection and Response 2024 Vendor Assessment (Doc #US51752324, November 2024)
  2. Darktrace Cyber AI Analyst Customer Fleet Data
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About the author
Mikey Anderson
Product Manager, Network Detection & Response
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