Evaluating Email Security: How to Select the Best Solution for Your Organization
In today’s saturated market for email security, it can be difficult to cut through the noise of AI hype and vendor claims. CISOs should be using a structured evaluation framework to support informed, objective comparisons of different vendors – to allow them to make the best decision for their organization.
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
Carlos Gray
Senior Product Marketing Manager, Email
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21
May 2025
When evaluating email security solutions, it’s crucial to move beyond marketing claims and focus on real-world performance. One of the most effective ways to achieve this is through an A/B comparison approach – a side-by-side evaluation of vendors based on consistent, predefined criteria.
This method cuts through biases, reveals true capability differences, and ensures that all solutions are assessed on a level playing field. It’s not just about finding an objectively good solution – it’s about finding the best solution for your organization’s specific needs.
An A/B comparison approach is particularly effective for three main reasons:
Eliminates bias: By comparing solutions under identical conditions, it’s easier to spot differences in performance without the fog of marketing jargon.
Highlights real capabilities: Direct side-by-side testing exposes genuine strengths and weaknesses, making it easier to judge which features are impactful versus merely decorative.
Encourages objective decision-making: This structured method reduces emotional or brand-driven decisions, focusing purely on metrics and performance.
Let’s look at the key factors to consider when setting up your evaluation to ensure a fair, accurate, and actionable comparison.
Deployment: Setting the stage for fair evaluation
To achieve a genuine comparison, deployment must be consistent across all evaluated solutions:
Establish the same scope: All solutions should be granted identical visibility across relevant tenants and domains to ensure parity.
Set a concrete timeline: Deploy and test each solution with the same dataset, at the same points in time. This allows you to observe differences in learning periods and adaptive capabilities.
Equal visibility and synchronized timelines prevent discrepancies that could skew your understanding of each vendor’s true capabilities. But remember – quicker results might not equal better learning or understanding!
Tuning and configurations: Optimizing for real-world conditions
Properly tuning and configuring each solution is critical for fair evaluation:
Compare on optimal performance: Consult with each vendor to understand what optimal deployment looks like for their solution, particularly if machine learning is involved.
Consider the long term: Configuration adjustments should be made with long-term usage in mind. Short-term fixes can mask long-term challenges.
Data visibility: Ensure each solution can retain and provide search capabilities on all data collected throughout the evaluation period.
These steps guarantee that you are comparing fully optimized versions of each platform, not underperforming or misconfigured ones.
Evaluation: Applying consistent metrics
Once deployment and configurations are aligned, the evaluation itself must be consistent, to prevent unfair scoring and help to identify true differences in threat detection and response capabilities.
Coordinate your decision criteria: Ensure all vendors are measured against the same set of criteria, established before testing begins.
Understand vendor threat classification: Each vendor may have different ways of classifying threats, so be sure to understand these nuances.
Maintain communication: If results seem inaccurate, engage with the vendors. Their response and remediation capabilities are part of the evaluation.
Making a decision: Look beyond the metrics
When it comes to reviewing the performance of each solution, it’s important to both consider and look beyond the raw data. This is about choosing the solution that best aligns with your specific business needs, which may include factors and features not captured in the results.
Evaluate based on results: Consider accuracy, threats detected, precision, and response effectiveness.
Evaluate beyond results: Assess the overall experience, including support, integrations, training, and long-term alignment with your security strategy.
Review and communicate: Internally review the findings and communicate them back to the vendors.
Choosing the right email security solution isn’t just about ticking boxes, it’s about strategic alignment with your organization’s goals and the evolving threat landscape. A structured, A/B comparison approach will help ensure that the solution you select is truly the best fit.
For a full checklist of the features and capabilities to compare, as well as how to perform a commercial and technical evaluation, check out the full Buyer’s Checklist for Evaluating Email Security.
[related-resource]
A Buyer’s Checklist for Evaluating Email Security
Get the most effective system for comparing email security solutions – based on real-world performance and measurable capabilities.
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.
Why Data Classification Isn’t Enough to Prevent Data Loss
In a world of growing data volume and diversity, protecting and keeping track of your organization’s sensitive information is increasingly complex – particularly when 63% of breaches stem from malicious insiders or human error. This blog explores how security teams can achieve visibility beyond the limits of data classification, without adding to the burden of data management.
Email bombing exposed: Darktrace’s email defense in action
Darktrace detected an email bomb attack flooding inboxes with high volumes of messages, uncovering unusual email patterns and subsequent network anomalies.
FedRAMP High-compliant email security protects federal agencies from nation-state attacks
Not only has Darktrace Federal achieved its FedRAMP High Authority to Operate, one of the few cybersecurity vendors to do this, but we have also released Darktrace Commercial Government Cloud High/Email, a FedRAMP High-compliant email security solution for customers using Microsoft Government Community Cloud High.
Marcus Fowler
CEO of Darktrace Federal and SVP of Strategic Engagements and Threats
Waterways: Coastal and inland rivers, shipping channels, and harbors
Ports: Terminals, piers, and facilities where cargo and passengers are transferred
Vessels: Commercial ships, barges, ferries, and support craft
Intermodal Connections: Railroads, highways, and logistics hubs that tie maritime transport into national and global supply chains
The Coast Guard plays a central role in ensuring the safety, security, and efficiency of the MTS, handling over $5.4 trillion in annual economic activity. As digital systems increasingly support operations across the MTS, from crane control to cargo tracking, cybersecurity has become essential to protecting this lifeline of U.S. trade and infrastructure.
Maritime Transportation Systems also enable international trade, making them prime targets for cyber threats from ransomware gangs to nation-state actors.
To defend against growing threats, the United States Coast Guard (USCG) has moved from encouraging cybersecurity best practices to enforcing them, culminating in a new mandate that goes into effect on July 16, 2025. These regulations aim to secure the digital backbone of the maritime industry.
Why maritime ports are at risk
Modern ports are a blend of legacy and modern OT, IoT, and IT digitally connected technologies that enable crane operations, container tracking, terminal storage, logistics, and remote maintenance.
Many of these systems were never designed with cybersecurity in mind, making them vulnerable to lateral movement and disruptive ransomware attack spillover.
The convergence of business IT networks and operational infrastructure further expands the attack surface, especially with the rise of cloud adoption and unmanaged IoT and IIoT devices.
Cyber incidents in recent years have demonstrated how ransomware or malicious activity can halt crane operations, disrupt logistics, and compromise safety at scale threatening not only port operations, but national security and economic stability.
Relevant cyber-attacks on maritime ports
Maersk & Port of Los Angeles (2017 – NotPetya): A ransomware attack crippled A.P. Moller-Maersk, the world’s largest shipping company. Operations at 17 ports, including the Port of Los Angeles, were halted due to system outages, causing weeks of logistical chaos.
Port of San Diego (2018 – Ransomware Attack): A ransomware attack targeted the Port of San Diego, disrupting internal IT systems including public records, business services, and dockside cargo operations. While marine traffic was unaffected, commercial activity slowed significantly during recovery.
Port of Houston (2021 – Nation-State Intrusion): A suspected nation-state actor exploited a known vulnerability in a Port of Houston web application to gain access to its network. While the attack was reportedly thwarted, it triggered a federal investigation and highlighted the vulnerability of maritime systems.
Jawaharlal Nehru Port Trust, India (2022 – Ransomware Incident): India’s largest container port experienced disruptions due to a ransomware attack affecting operations and logistics systems. Container handling and cargo movement slowed as IT systems were taken offline during recovery efforts.
A regulatory shift: From guidance to enforcement
Since the Maritime Transportation Security Act (MTSA) of 2002, ports have been required to develop and maintain security plans. Cybersecurity formally entered the regulatory fold in 2020 with revisions to 33 CFR Part 105 and 106, requiring port authorities to assess and address computer system vulnerabilities.
In January 2025, the USCG finalized new rules to enforce cybersecurity practices across the MTS. Key elements include (but are not limited to):
A dedicated cyber incident response plan (PR.IP-9)
Routine cybersecurity risk assessments and exercises (ID.RA)
Designation of a cybersecurity officer and regular workforce training (section 3.1)
Controls for access management, segmentation, logging, and encryption (PR.AC-1:7)
Supply chain risk management (ID.SC)
Incident reporting to the National Response Center
Maritime ports operate in hybrid environments spanning business IT systems (finance, HR, ERP), industrial OT (cranes, gates, pumps, sensors), and an increasing array of cloud and SaaS platforms.
Darktrace is the only vendor that provides native visibility and threat detection across OT/IoT, IT, cloud, and SaaS environments — all in a single platform. This means:
Cranes and other physical process control networks are monitored in the same dashboard as Active Directory and Office 365.
Threats that start in the cloud (e.g., phishing, SaaS token theft) and pivot or attempt to pivot into OT are caught early — eliminating blind spots that siloed tools miss.
This unification is critical to meeting USCG requirements for network-wide monitoring, risk identification, and incident response.
AI that understands your environment. Not just known threats
Darktrace’s AI doesn’t rely on rules or signatures. Instead, it uses Self-Learning AI TM that builds a unique “pattern of life” for every device, protocol, user, and network segment, whether it’s a crane router or PLC, SCADA server, Workstation, or Linux file server.
No predefined baselines or manual training
Real-time anomaly detection for zero-days, ransomware, and supply chain compromise
Continuous adaptation to new devices, configurations, and operations
This approach is critical in diverse distributed OT environments where change and anomalous activity on the network are more frequent. It also dramatically reduces the time and expertise needed to classify and inventory assets, even for unknown or custom-built systems.
Supporting incident response requirements
A key USCG requirement is that cybersecurity plans must support effective incident response.
Key expectations include:
Defined response roles and procedures: Personnel must know what to do and when (RS.CO-1).
Timely reporting: Incidents must be reported and categorized according to established criteria (RS.CO-2, RS.AN-4).
Effective communication: Information must be shared internally and externally, including voluntary collaboration with law enforcement and industry peers (RS.CO-3 through RS.CO-5).
Thorough analysis: Alerts must be investigated, impacts understood, and forensic evidence gathered to support decision-making and recovery (RS.AN-1 through RS.AN-5).
Swift mitigation: Incidents must be contained and resolved efficiently, with newly discovered vulnerabilities addressed or documented (RS.MI-1 through RS.MI-3).
Ongoing improvement: Organizations must refine their response plans using lessons learned from past incidents (RS.IM-1 and RS.IM-2).
That means detections need to be clear, accurate, and actionable.
Darktrace cuts through the noise using AI that prioritizes only high-confidence incidents and provides natural-language narratives and investigative reports that explain:
What’s happening, where it’s happening, when it’s happening
Why it’s unusual
How to respond
Result: Port security teams often lean and multi-tasked can meet USCG response-time expectations and reporting needs without needing to scale headcount or triage hundreds of alerts.
Built-for-edge deployment
Maritime environments are constrained. Many traditional SaaS deployment types often are unsuitable for tugboats, cranes, or air-gapped terminal systems.
Darktrace builds and maintains its own ruggedized, purpose-built appliances and unique virtual deployment options that:
Deploy directly into crane networks or terminal enclosures
Require no configuration or tuning, drop-in ready
Support secure over-the-air updates and fleet management
Operate without cloud dependency, supporting isolated and air-gapped systems
Use case: Multiple ports have been able to deploy Darktrace directly into the crane’s switch enclosure, securing lateral movement paths without interfering with the crane control software itself.
Darktrace visualizes real-time connectivity and attack pathways across IT, OT, and IoT it and integrates with firewalls (e.g., Fortinet, Cisco, Palo Alto) to enforce segmentation using AI insights alongside Darktrace’s own native autonomous and human confirmed response capabilities.
Benefits of autonomous and human confirmed response:
Auto-isolate rogue devices before the threat can escalate
Quarantine a suspicious connectivity with confidence operations won’t be halted
Autonomously buy time for human responders during off-hours or holidays
This ensures segmentation isn't just documented but that in the case of its failure or exploitation responses are performed as a compensating control
No reliance on 3rd parties or external connectivity
Darktrace’s supply chain integrity is a core part of its value to critical infrastructure customers. Unlike solutions that rely on indirect data collection or third-party appliances, Darktrace:
Uses in-house engineered sensors and appliances
Does not require transmission of data to or from the cloud
This ensures confidence in both your cyber visibility and the security of the tools you deploy.
See examples here of how Darktrace stopped supply chain attacks:
With a self-learning system that adapts to each unique port environment, Darktrace helps maritime operators not just comply but build lasting cyber resilience in a high-threat landscape.
Cybersecurity is no longer optional for U.S. ports its operationally and nationally critical. Darktrace delivers the intelligence, automation, and precision needed to meet USCG requirements and protect the digital lifeblood of the modern port.
Catching a RAT: How Darktrace Neutralized AsyncRAT
What is a RAT?
As the proliferation of new and more advanced cyber threats continues, the Remote Access Trojan (RAT) remains a classic tool in a threat actor's arsenal. RATs, whether standardized or custom-built, enable attackers to remotely control compromised devices, facilitating a range of malicious activities.
What is AsyncRAT?
Since its first appearance in 2019, AsyncRAT has become increasingly popular among a wide range of threat actors, including cybercriminals and advanced persistent threat (APT) groups.
Originally available on GitHub as a legitimate tool, its open-source nature has led to widespread exploitation. AsyncRAT has been used in numerous campaigns, including prolonged attacks on essential US infrastructure, and has even reportedly penetrated the Chinese cybercriminal underground market [1] [2].
How does AsyncRAT work?
Original source code analysis of AsyncRAT demonstrates that once installed, it establishes persistence via techniques such as creating scheduled tasks or registry keys and uses SeDebugPrivilege to gain elevated privileges [3].
Its key features include:
Keylogging
File search
Remote audio and camera access
Exfiltration techniques
Staging for final payload delivery
These are generally typical functions found in traditional RATs. However, it also boasts interesting anti-detection capabilities. Due to the popularity of Virtual Machines (VM) and sandboxes for dynamic analysis, this RAT checks for the manufacturer via the WMI query 'Select * from Win32_ComputerSystem' and looks for strings containing 'VMware' and 'VirtualBox' [4].
Darktrace’s coverage of AsyncRAT
In late 2024 and early 2025, Darktrace observed a spike in AsyncRAT activity across various customer environments. Multiple indicators of post-compromise were detected, including devices attempting or successfully connecting to endpoints associated with AsyncRAT.
On several occasions, Darktrace identified a clear association with AsyncRAT through the digital certificates of the highlighted SSL endpoints. Darktrace’s Real-time Detection effectively identified and alerted on suspicious activities related to AsyncRAT. In one notable incident, Darktrace’s Autonomous Response promptly took action to contain the emerging threat posed by AsyncRAT.
AsyncRAT attack overview
On December 20, 2024, Darktrace first identified the use of AsyncRAT, noting a device successfully establishing SSL connections to the uncommon external IP 185.49.126[.]50 (AS199654 Oxide Group Limited) via port 6606. The IP address appears to be associated with AsyncRAT as flagged by open-source intelligence (OSINT) sources [5]. This activity triggered the device to alert the ‘Anomalous Connection / Rare External SSL Self-Signed' model.
Figure 1: Model alert in Darktrace / NETWORK showing the repeated SSL connections to a rare external Self-Signed endpoint, 185.49.126[.]50.
Following these initial connections, the device was observed making a significantly higher number of connections to the same endpoint 185.49.126[.]50 via port 6606 over an extended period. This pattern suggested beaconing activity and triggered the 'Compromise/Beaconing Activity to External Rare' model alert.
Further analysis of the original source code, available publicly, outlines the default ports used by AsyncRAT clients for command-and-control (C2) communications [6]. It reveals that port 6606 is the default port for creating a new AsyncRAT client. Darktrace identified both the Certificate Issuer and the Certificate Subject as "CN=AsyncRAT Server". This SSL certificate encrypts the packets between the compromised system and the server. These indicators of compromise (IoCs) detected by Darktrace further suggest that the device was successfully connecting to a server associated with AsyncRAT.
Figure 2: Model alert in Darktrace / NETWORK displaying the Digital Certificate attributes, IP address and port number associated with AsyncRAT.
Figure 3: Darktrace’s detection of repeated connections to the suspicious IP address 185.49.126[.]50 over port 6606, indicative of beaconing behavior.
Figure 4: Darktrace's Autonomous Response actions blocking the suspicious IP address,185.49.126[.]50.
A few days later, the same device was detected making numerous connections to a different IP address, 195.26.255[.]81 (AS40021 NL-811-40021), via various ports including 2106, 6606, 7707, and 8808. Notably, ports 7707 and 8808 are also default ports specified in the original AsyncRAT source code [6].
Figure 5: Darktrace’s detection of connections to the suspicious endpoint 195.26.255[.]81, where the default ports (6606, 7707, and 8808) for AsyncRAT were observed.
Similar to the activity observed with the first endpoint, 185.49.126[.]50, the Certificate Issuer for the connections to 195.26.255[.]81 was identified as "CN=AsyncRAT Server". Further OSINT investigation confirmed associations between the IP address 195.26.255[.]81 and AsyncRAT [7].
Figure 6: Darktrace's detection of a connection to the suspicious IP address 195.26.255[.]81 and the domain name identified under the common name (CN) of a certificate as AsyncRAT Server.
Once again, Darktrace's Autonomous Response acted swiftly, blocking the connections to 195.26.255[.]81 throughout the observed AsyncRAT activity.
Figure 7: Darktrace's Autonomous Response actions were applied against the suspicious IP address 195.26.255[.]81.
A day later, Darktrace again alerted to further suspicious activity from the device. This time, connections to the suspicious endpoint 'kashuub[.]com' and IP address 191.96.207[.]246 via port 8041 were observed. Further analysis of port 8041 suggests it is commonly associated with ScreenConnect or Xcorpeon ASIC Carrier Ethernet Transport [8]. ScreenConnect has been observed in recent campaign’s where AsyncRAT has been utilized [9]. Additionally, one of the ASN’s observed, namely ‘ASN Oxide Group Limited’, was seen in both connections to kashuub[.]com and 185.49.126[.]50.
This could suggest a parallel between the two endpoints, indicating they might be hosting AsyncRAT C2 servers, as inferred from our previous analysis of the endpoint 185.49.126[.]50 and its association with AsyncRAT [5]. OSINT reporting suggests that the “kashuub[.]com” endpoint may be associated with ScreenConnect scam domains, further supporting the assumption that the endpoint could be a C2 server.
Darktrace’s Autonomous Response technology was once again able to support the customer here, blocking connections to “kashuub[.]com”. Ultimately, this intervention halted the compromise and prevented the attack from escalating or any sensitive data from being exfiltrated from the customer’s network into the hands of the threat actors.
Figure 8: Darktrace’s Autonomous Response applied a total of nine actions against the IP address 191.96.207[.]246 and the domain 'kashuub[.]com', successfully blocking the connections.
Due to the popularity of this RAT, it is difficult to determine the motive behind the attack; however, from existing knowledge of what the RAT does, we can assume accessing and exfiltrating sensitive customer data may have been a factor.
Conclusion
While some cybercriminals seek stability and simplicity, openly available RATs like AsyncRAT provide the infrastructure and open the door for even the most amateur threat actors to compromise sensitive networks. As the cyber landscape continually shifts, RATs are now being used in all types of attacks.
Darktrace’s suite of AI-driven tools provides organizations with the infrastructure to achieve complete visibility and control over emerging threats within their network environment. Although AsyncRAT’s lack of concealment allowed Darktrace to quickly detect the developing threat and alert on unusual behaviors, it was ultimately Darktrace Autonomous Response's consistent blocking of suspicious connections that prevented a more disruptive attack.
Credit to Isabel Evans (Cyber Analyst), Priya Thapa (Cyber Analyst) and Ryan Traill (Analyst Content Lead)
Appendices
Real-time Detection Models
Compromise / Suspicious SSL Activity
Compromise / Beaconing Activity To External Rare
Compromise / High Volume of Connections with Beacon Score
Anomalous Connection / Suspicious Self-Signed SSL
Compromise / Sustained SSL or HTTP Increase
Compromise / SSL Beaconing to Rare Destination
Compromise / Suspicious Beaconing Behaviour
Compromise / Large Number of Suspicious Failed Connections
Autonomous Response Models
Antigena / Network / Significant Anomaly / Antigena Controlled and Model Alert
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![Model alert in Darktrace / NETWORK showing the repeated SSL connections to a rare external Self-Signed endpoint, 185.49.126[.]50.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/6823ad5f8454ff831da3182a_Screenshot%202025-05-13%20at%201.35.56%E2%80%AFPM.avif)
![Darktrace’s detection of repeated connections to the suspicious IP address 185.49.126[.]50 over port 6606, indicative of beaconing behavior.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/6823adc5ac5c997938babf30_Screenshot%202025-05-13%20at%201.38.15%E2%80%AFPM.avif)
![Darktrace's Autonomous Response actions blocking the suspicious IP address,185.49.126[.]50.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/6825268603a7a2b1459c9fea_Figure%204.avif)
![Darktrace’s detection of connections to the suspicious endpoint 195.26.255[.]81, where the default ports (6606, 7707, and 8808) for AsyncRAT were observed.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/6823ae6e325a742b23ef6e6d_Screenshot%202025-05-13%20at%201.41.09%E2%80%AFPM.avif)
![Darktrace's detection of a connection to the suspicious IP address 195.26.255[.]81 and the domain name identified under the common name (CN) of a certificate as AsyncRAT Server](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/6823aea233fc6374c1432604_Screenshot%202025-05-13%20at%201.42.00%E2%80%AFPM.avif)
![Darktrace’s Autonomous Response applied a total of nine actions against the IP address 191.96.207[.]246 and the domain 'kashuub[.]com', successfully blocking the connections.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/6823af1b3cbc7734f47fc15b_Screenshot%202025-05-13%20at%201.43.56%E2%80%AFPM.avif)