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May 13, 2025

Catching a RAT: How Darktrace Neutralized AsyncRAT

Darktrace's AI-driven tools identified and disrupted AsyncRAT activity, detecting suspicious connections and blocking them autonomously. This proactive response prevented the compromise from escalating and safeguarded sensitive data from exfiltration.
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
Isabel Evans
Cyber Analyst
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13
May 2025

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.

Model alert in Darktrace / NETWORK showing the repeated SSL connections to a rare external Self-Signed endpoint, 185.49.126[.]50.
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.

Model alert in Darktrace / NETWORK displaying the Digital Certificate attributes, IP address and port number associated with AsyncRAT.
Figure 2: Model alert in Darktrace / NETWORK displaying the Digital Certificate attributes, IP address and port number associated with AsyncRAT.
Darktrace’s detection of repeated connections to the suspicious IP address 185.49.126[.]50 over port 6606, indicative of beaconing behavior.
Figure 3: Darktrace’s detection of repeated connections to the suspicious IP address 185.49.126[.]50 over port 6606, indicative of beaconing behavior.
Darktrace's Autonomous Response actions blocking the suspicious IP address,185.49.126[.]50.
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].

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.
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].

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
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.

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.
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
    •  
    • Antigena / Network / Significant      Anomaly / Antigena Enhanced Monitoring from Client Block

List of IoCs

·     185.49.126[.]50 - IP – AsyncRAT C2 Endpoint

·     195.26.255[.]81 – IP - AsyncRAT C2 Endpoint

·      191.96.207[.]246 – IP – Likely AsyncRAT C2 Endpoint

·     CN=AsyncRAT Server - SSL certificate - AsyncRATC2 Infrastructure

·      Kashuub[.]com– Hostname – Likely AsyncRAT C2 Endpoint

MITRE ATT&CK Mapping:

Tactic –Technique – Sub-Technique  

 

Execution– T1053 - Scheduled Task/Job: Scheduled Task

DefenceEvasion – T1497 - Virtualization/Sandbox Evasion: System Checks

Discovery– T1057 – Process Discovery

Discovery– T1082 – System Information Discovery

LateralMovement - T1021.001 - Remote Services: Remote Desktop Protocol

Collection/ Credential Access – T1056 – Input Capture: Keylogging

Collection– T1125 – Video Capture

Commandand Control – T1105 - Ingress Tool Transfer

Commandand Control – T1219 - Remote Access Software

Exfiltration– T1041 - Exfiltration Over C2 Channel

 

References

[1]  https://blog.talosintelligence.com/operation-layover-how-we-tracked-attack/

[2] https://intel471.com/blog/china-cybercrime-undergrond-deepmix-tea-horse-road-great-firewall

[3] https://www.attackiq.com/2024/08/01/emulate-asyncrat/

[4] https://www.fortinet.com/blog/threat-research/spear-phishing-campaign-with-new-techniques-aimed-at-aviation-companies

[5] https://www.virustotal.com/gui/ip-address/185.49.126[.]50/community

[6] https://dfir.ch/posts/asyncrat_quasarrat/

[7] https://www.virustotal.com/gui/ip-address/195.26.255[.]81

[8] https://www.speedguide.net/port.php?port=8041

[9] https://www.esentire.com/blog/exploring-the-infection-chain-screenconnects-link-to-asyncrat-deployment

[10] https://scammer.info/t/taking-out-connectwise-sites/153479/518?page=26

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
Isabel Evans
Cyber Analyst

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September 23, 2025

It’s Time to Rethink Cloud Investigations

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Cloud Breaches Are Surging

Cloud adoption has revolutionized how businesses operate, offering speed, scalability, and flexibility. But for security teams, this transformation has introduced a new set of challenges, especially when it comes to incident response (IR) and forensic investigations.

Cloud-related breaches are skyrocketing – 82% of breaches now involve cloud-stored data (IBM Cost of a Data Breach, 2023). Yet incidents often go unnoticed for days: according to a 2025 report by Cybersecurity Insiders, of the 65% of organizations experienced a cloud-related incident in the past year, only 9% detected it within the first hour, and 62% took more than 24 hours to remediate it (Cybersecurity Insiders, Cloud Security Report 2025).

Despite the shift to cloud, many investigation practices remain rooted in legacy on-prem approaches. According to a recent report, 65% of organizations spend approximately 3-5 days longer when investigating an incident in the cloud vs. on premises.

Cloud investigations must evolve, or risk falling behind attackers who are already exploiting the cloud’s speed and complexity.

4 Reasons Cloud Investigations Are Broken

The cloud’s dynamic nature – with its ephemeral workloads and distributed architecture – has outpaced traditional incident response methods. What worked in static, on-prem environments simply doesn’t translate.

Here’s why:

  1. Ephemeral workloads
    Containers and serverless functions can spin up and vanish in minutes. Attackers know this as well – they’re exploiting short-lived assets for “hit-and-run” attacks, leaving almost no forensic footprint. If you’re relying on scheduled scans or manual evidence collection, you’re already too late.
  2. Fragmented tooling
    Each cloud provider has its own logs, APIs, and investigation workflows. In addition, not all logs are enabled by default, cloud providers typically limit the scope of their logs (both in terms of what data they collect and how long they retain it), and some logs are only available through undocumented APIs. This creates siloed views of attacker activity, making it difficult to piece together a coherent timeline. Now layer in SaaS apps, Kubernetes clusters, and shadow IT — suddenly you’re stitching together 20+ tools just to find out what happened. Analysts call it the ‘swivel-chair Olympics,’ and it’s burning hours they don’t have.
  3. SOC overload
    Analysts spend the bulk of their time manually gathering evidence and correlating logs rather than responding to threats. This slows down investigations and increases burnout. SOC teams are drowning in noise; they receive thousands of alerts a day, the majority of which never get touched. False positives eat hundreds of hours a month, and consequently burnout is rife.  
  4. Cost of delay
    The longer an investigation takes, the higher its cost. Breaches contained in under 200 days save an average of over $1M compared to those that linger (IBM Cost of a Data Breach 2025).

These challenges create a dangerous gap for threat actors to exploit. By the time evidence is collected, attackers may have already accessed or exfiltrated data, or entrenched themselves deeper into your environment.

What’s Needed: A New Approach to Cloud Investigations

It’s time to ditch the manual, reactive grind and embrace investigations that are automated, proactive, and built for the world you actually defend. Here’s what the next generation of cloud forensics must deliver:

  • Automated evidence acquisition
    Capture forensic-level data the moment a threat is detected and before assets disappear.
  • Unified multi-cloud visibility
    Stitch together logs, timelines, and context across AWS, Azure, GCP, and hybrid environments into a single unified view of the investigation.
  • Accelerated investigation workflows
    Reduce time-to-insight from hours or days to minutes with automated analysis of forensic data, enabling faster containment and recovery.
  • Empowered SOC teams
    Fully contextualised data and collaboration workflows between teams in the SOC ensure seamless handover, freeing up analysts from manual collection tasks so they can focus on what matters: analysis and response.

Attackers are already leveraging the cloud’s agility. Defenders must do the same — adopting solutions that match the speed and scale of modern infrastructure.

Cloud Changed Everything. It’s Time to Change Investigations.  

The cloud fundamentally reshaped how businesses operate. It’s time for security teams to rethink how they investigate threats.

Forensics can no longer be slow, manual, and reactive. It must be instant, automated, and cloud-first — designed to meet the demands of ephemeral infrastructure and multi-cloud complexity.

The future of incident response isn’t just faster. It’s smarter, more scalable, and built for the environments we defend today, not those of ten years ago.  

On October 9th, Darktrace is revealing the next big thing in cloud security. Don’t miss it – sign up for the webinar.

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Kellie Regan
Director, Product Marketing - Cloud Security

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September 22, 2025

Understanding the Canadian Critical Cyber Systems Protection Act

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Introduction: The Canadian Critical Cyber Systems Protection Act

On 18 June 2025, the Canadian federal Government introduced Bill C-8 which, if adopted following completion of the legislative process, will enact the Critical Cyber Systems Protection Act (CCSPA) and give Canada its first federal, cross-sector and legally binding cybersecurity regime for designated critical infrastructure providers. As of August 2025, the Bill has completed first reading and stands at second reading in the Canadian House of Commons.

Political context

The measure revives most of the stalled 2022 Bill C-26 “An Act Respecting Cyber Security” which “died on Paper” when Parliament was prorogued in January 2025, in the wake of former Prime Minister Justin Trudeau’s resignation.

The new government, led by Mark Carney since March 2025, has re-tabled the package with the same two-part structure: (1) amendments to the Telecommunications Act that enable security directions to telecoms; and (2) a new CCSPA setting out mandatory cybersecurity duties for designated operators. This blog focuses on the latter.

If enacted, Canada will join fellow Five Eyes partners such as the United Kingdom and Australia, which already impose statutory cyber-security duties on operators of critical national infrastructure.

The case for new cybersecurity legislation in Canada

The Canadian cyber threat landscape has expanded. The country's national cyber authority, the Canadian Centre for Cybersecurity (Cyber Centre), recently assessed that the number of cyber incidents has “sharply increased” in the last two years, as has the severity of those incidents, with essential services providers among the targets. Likewise, in its 2025-2026 National Cyber Threat Assessment, the Cyber Centre warned that AI technologies are “amplifying cyberspace threats” by lowering barriers to entry, improving the speed and sophistication of social-engineering attacks and enabling more precise operations.

This context mirrors what we are seeing globally: adversaries, including state actors, are taking advantage of the availability and sophistication of AI tools, which they have leverage to amplify the effectiveness of their operations. In this increasingly complex landscape, regulation must keep pace and evolve in step with the risk.

What the Canadian Critical Cyber Systems Protection Act aims to achieve

  • If enacted, the CCSPA will apply to operators in federally regulated critical infrastructure sectors which are vital to national security and public safety, as further defined in “Scope” below (the “Regulated Entities”), to adopt and comply with a minimum standard of cybersecurity duties (further described below)  which align with those its Five Eyes counterparts are already adhering to.

Who does the CCSPA apply to

The CCSPA would apply to designated operators that deliver services or systems within federal jurisdiction in the following priority areas:

  • telecommunications services
  • interprovincial or international pipeline and power line systems, nuclear energy systems, transportation systems
  • banking and clearing  
  • settlement systems

The CCSPA would also grant the Governor in Council (Federal Cabinet) with powers to add or remove entities in scope via regulation.

Scope of the CCSPA

The CCSPA introduces two key instruments:

First, it strengthens cyber threat information sharing between responsible ministers, sector regulators, and the Communications Security Establishment (through the Cyber Centre).

Second, it empowers the Governor in Council (GIC) to issue Cyber Security Directions (CSDs) - binding orders requiring a designated operator to implement specified measures to protect a critical cyber system within defined timeframes.

CSDs may be tailored to an individual operator or applied to a class of operators and can address technology, process, or supplier risks. To safeguard security and commercial confidentiality, the CCSPA restricts disclosure of the existence or content of a CSD except as necessary to carry it out.

Locating decision-making with the GIC ensures that CSDs are made with a cross-government view that weighs national security, economic priorities and international agreement.

New obligations for designated providers

The CCSPA would impose key cybersecurity compliance and obligations on designated providers. As it stands, this includes:

  1. Establishing and maintaining cybersecurity programs: these will need to be comprehensive, proportionate and developed proactively. Once implemented, they will need to be continuously reviewed
  2. Mitigating supply chain risks: Regulated Entities will be required to assess their third-party products and services by conducting a supply chain analysis, and take active steps to mitigate any identified risks
  3. Reporting incidents:  Regulated Entities will need to be more transparent with their reporting, by making the Communications Security Establishment (CSE) aware of any incident which has, or could potentially have, an impact on a critical system. The reports must be made within specific timelines, but in any event within no more than 72 hours;
  4. Compliance with cybersecurity directions:  the government will, under the CCSPA, have the authority to issue cybersecurity directives in an effort to remain responsive to emerging threats, which Regulated Entities will be required to follow once issued
  5. Record keeping: this shouldn’t be a surprise to many of those Regulated Entities which fall in scope, which are already likely to be subject to record keeping requirements. Regulated Entities should expect to be maintaining records and conducting audits of their systems and processes against the requirements of the CCSPA

It should be noted, however, that this may be subject to change, so Regulated Entities should keep an eye on the progress of the Bill as it makes its way through parliament.

Enforcement of the Act would be carried out by sector-specific regulators identified in the Act such as the Office of the Superintendent of Financial Institutions, Minister of Transport, Canada Energy Regulator, Canadian Nuclear Safety Commission and the Ministry of Industry.

What are the penalties for CCSPA non-compliance?

When assessing the penalties associated with non-compliance with the requirements of the CCSPA, it is clear that such non-compliance will be taken seriously, and the severity of the penalties follows the trend of those applied by the European Union to key pieces of EU legislation. The “administrative monetary penalties” (AMPs) set by regulation could see fines being applied of up to C$1 million for individuals and up to C$15 million for organizations.

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