Article
US Government Alerts of Imminent Attacks Against the Healthcare Sector by Trickbot Group
Arete Analysis

Executive Summary
Last week, the Cybersecurity and Infrastructure Security Agency (CISA) in collaboration with the Federal Bureau of Investigation (FBI), and the Department of Health and Human Services (HHS) released the following alert: AA20-302A – Ransomware Activity Targeting the Healthcare and Public Health Sector.
The alert informs that there is credible intelligence of an increased and imminent cybercrime threat to U.S. hospitals and healthcare providers associated with the Trickbot and BazarLoader trojans that often leads to ransomware like the Ryuk and Conti ransomware. The alert also mentions the Trickbot Anchor tool set and Anchor DNS tool developed by this group.
News of these attacks against the Healthcare sector are of special concern due to the recent increase of COVID-19 cases in the US and evidence that shows ransomware attacks against the healthcare sector have been associated with persons losing their lives due to services being routed to nearby hospitals and laboratory results not being quickly delivered electronically to the providers.
Arete statistics and Intel from Arete’s Fusion Center and Open-source intelligence (OSINT) shows that this new wave of attacks since October 2020 have a slight change in TTPs and the BazarLoader malware has now been observed in systems compromised with Ryuk.
The Arete incident response (IR) practice has responded to more than ninety (90) Ryuk engagements since 2019 with more than six breach responses engagements just in the month of October 2020.
Based on Intelligence gathered from our DFIR cases, Arete’s Fusion Center had developed countermeasures deployed in the SentinelOne EDR platform to detect these threats and our Managed Detection and Response (MDR) team has been handling detections at our client’s sites.
This article is meant to share with the community Arete’s statistics and our assessment based on breach response engagements.
Statistical Data from Arete’s Metrics
The information listed below is based on Ryuk cases investigated by Arete IR since January 2019. Our IR and Data Analytics practices work together to track key data points for every ransomware engagement. Our IR practice tracks data points on the ransomware variant and collects statis-tics based on handled engagements:
Since 2019, Arete has responded to Ryuk cases in some of the following sectors:
Healthcare: 19 | Professional Service: 28 | Public services: 21 | Manufacturing: 11 | Technology/Engineing/ Telecom: 6 | Critical Infrastructure: 1
Average duration of business downtime: 9.47 days
Average original ransom demand in bitcoin: 125.39 BTC
Average final ransom demand in bitcoin: 72.58 BTC
Average ransom demand paid in US dollars: $621,064.05
Minimum ransom demand paid in US dollars: $10,000.00
Maximum ransom demand paid in US dollars: $5,177,510.78
Remote access is the most common method of intrusion found 39.34% of the times
During the Ryuk dwell time this year, Arete responded to ten (10) Conti ransomware engagements
Ryuk Ransomware Overview
Since August 2018, a Russian-based cybercrime group has been operating a ransomware known as Ryuk (a customized version of Hermes commodity ransomware).
The industry saw a sudden drop of Ryuk, starting around the time that COVID-19 had its major impact in March 2020. This is also around the same time that a very similar, Conti ransomware, began to kick-off, leading many to believe that Conti was merely a rebrand of Ryuk. The data suggests though that it is possible that Conti was a failed rebrand since Arete IR has not been engaged with Conti infected clients since Ryuk attacks started again in October 2020.
Ryuk typically compromises networks through Trickbot, or Emotet then delivering Trickbot. Trickbot has recently been in the news in the cyber industry due to Microsoft’s approval via a court order to engage in disruption efforts of this botnet. With this active disruption campaign, it is possible that the sudden return and up-tick of Ryuk infections is due to the Russian cybercrime group acting in retaliation utilizing their more mature ransomware product, Ryuk, as opposed to the potentially rebranded, Conti, which could still have been in a testing phase. This is based on the sudden stop of Conti and up-rise of Ryuk in line with the disruption efforts from Microsoft.
According to Microsoft, they initially disabled sixty-two (62) of the initially identified sixty-nine (69) Trickbot servers. Almost immediately, fifty-nine (59) new servers were attempted to be added to the Trickbot infrastructure. As of October 20, 2020, fifty-eight (58) of the new servers have also been disabled leaving a total number of eight (8) known active Trickbot servers.
Ryuk Wave Crashing on US Healthcare
Of the more than ninety (90) total Ryuk ransomware engagements that Arete IR has led since May 2019, nineteen (19) of those engagements were for a client in the healthcare industry (23%). Out of the seven (7) engagements of Ryuk ransomware that Arete IR has led since it re-emerged in October 2020, the most recent case is the only client that is in the healthcare industry (14%). This evidence shows it is not typical for Ryuk attacks to be focused primarily on the healthcare industry. This could further backup the theory that the impending Ryuk wave of attacks on the healthcare
industry could be retaliation for Microsoft’s disruption campaign against the Trickbot infrastructure that Ryuk is known for utilizing for initial intrusion.

Recommendations
Install an Endpoint Detection and Response (EDR) solution with the capability to halt detected processes and isolate systems on the network, based on identified conditions
Block: Any known attacker C2s in the firewall; A high number of SMB connection attempts from one system to others in the network over a short period of time
Implement: A system enforced password policy to force users into changing passwords at least every 90 days; Multifactor authentication (MFA) on RDP and VPN access
If not needed, eliminate vulnerable RDP ports exposed to the internet
Perform: Dark web monitoring periodically to verify if data from the organization is available for sell in the black market; Penetration tests • Periodically patch systems and update tools
Monitor: Connections to the network from suspicious locations; Downloadsuploads of files to file sharing services over non-standard hours, not commonly used in the organization, etc; Uploads of files from Domain Controllers to the internet; Network scans from uncommon servers (e.g. RDP server)
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Article
Attack Patterns in Settra Incidents
Recent Settra ransomware incidents demonstrate a consistent operational pattern involving compromised credentials, VPN access, and the deployment of ransomware executables tailored to victim environments. Researchers have observed Settra naming ransomware executables after the targeted organization's domain while following similar attack sequences across multiple intrusions. Arete has also identified overlapping tactics, techniques, and tools in Settra engagements observed from June to August, including the use of MeshAgent for remote access and Bring Your Own Vulnerable Driver (BYOVD) techniques to weaken endpoint security controls.
What’s Notable and Unique
Settra operators have been observed naming ransomware executables after the victim organization's domain, creating a direct association between the payload and the targeted environment.
Initial access vectors have included targeting exposed VPN infrastructure and the use of compromised credentials, reducing the need for traditional exploitation of vulnerabilities.
Arete observed MeshAgent in multiple Settra engagements, which provides threat actors with a mechanism for remote access and continued activity within compromised environments.
Settra engagements have also included Bring Your Own Vulnerable Driver (BYOVD) activity, which can be used to bypass or impair security controls by abusing legitimate but vulnerable drivers.
Analyst Comments
Recent Settra activity demonstrates how ransomware operators can combine credential-based access, remote management tooling, and security control evasion techniques to establish and maintain access before ransomware deployment. The repeated use of similar tools and operational patterns across incidents provides useful detection opportunities for defenders. Organizations should closely monitor VPN authentication activity, unusual use of compromised credentials, unexpected MeshAgent deployment, ransomware executables with victim-specific naming conventions, and suspicious driver activity associated with attempts to disable or bypass endpoint security controls.
Arete’s MDR practice detects Settra’s full attack chain, with special attention to the staging of BYOVD activity for defense evasion. However, for us to detect it, SentinelOne needs to be fully deployed across an environment. To support organizations with full deployment, Arete offers SentinelOne Deployment Assistance. This service is designed to ensure that SentinelOne is deployed across all eligible endpoints, eliminating coverage gaps that could otherwise expose the organization to ransomware, malware, credential theft, and other advanced threats. Through endpoint discovery, inventory reconciliation, and deployment assistance, Arete helps organizations achieve comprehensive protection and maximize the effectiveness of their SentinelOne investment. Contact clientcares@areteir.com to learn more.
Sources
Ready, Settra, Go: New Settra Ransomware Variant Deploys MeshAgent RMM
Article
AI Agents Used in Campaign Against PaperCut
In late August, a threat actor used hundreds of AI agents to develop and launch a global exploitation campaign targeting vulnerable PaperCut NG and MF servers. PaperCut is print management software, and researchers determined that the operation compromised at least 440 PaperCut instances linked to 395 distinct organizations across 48 countries. The AI agents were tasked with building, testing, and refining exploits for CVE-2026-81578 and CVE-2026-82078 both security flaws affecting PaperCut software and flagged as actively exploited earlier this month. It is currently unclear if the threat actor is solely focused on access development to be handed off to other affiliated actors, or if they will directly leverage their access to achieve follow-on objectives such as data theft or ransomware deployment.
What’s Notable and Unique
Researchers observed three attack paths following the exploitation of vulnerable PaperCut servers. Threat actors would harvest credentials from LSASS memory and registry secrets to perform pass-the-hash attacks, leverage older unpatched Windows vulnerabilities (CVE-2021-42278 and CVE-2021-42287) to escalate privileges in unpatched environments, or, in some cases, directly add newly created accounts to the Domain Admins group when PaperCut was running with domain-level privileges.
Upon achieving remote code execution and credential harvesting within a self-hosted lab environment, the threat actor deployed hundreds of AI-powered agents that leveraged OpenAI Codex, DeepSeek models, and publicly available offensive security tools, including Mimikatz, SharpHound, Certipy, Rubeus, and Impacket, to automate reconnaissance, exploitation, and post-compromise activities. The attackers subsequently used a DCSync attack to obtain a database dump containing domain credentials.
Analyst Comments
The observed activity demonstrates how threat actors are increasingly leveraging AI and large language models (LLMs) to accelerate cyber operations at unprecedented speed and scale. In this campaign, the adversary progressed from exploit development to remote code execution within hours and, in some cases, achieved Domain Administrator privileges in as little as five minutes. The AI-assisted workflow enabled rapid reconnaissance, exploitation, credential theft, privilege escalation, and lateral movement, allowing the compromise of multiple organizations within seconds. This activity highlights the growing threat posed by AI-enabled adversaries capable of conducting large-scale intrusions with greater efficiency and operational velocity. Organizations affected by the PaperCut vulnerabilities are strongly advised to apply the latest security updates and implement the vendor's recommended mitigation measures to reduce the risk of compromise and unauthorized access.
Sources
Agents Gone Wild: An AI-Orchestrated Global Campaign Against PaperCut NG/MF
AI-powered attack exploited PaperCut flaws to hack 395 organizations
PaperCut Attacker Uses Hundreds of AI Agents to Compromise 440+ Instances
Article
Adversarial AI Evolves from Prompting to Autonomous Attack Workflows
Cybercriminals and state-linked threat actors are increasingly incorporating artificial intelligence (AI) into multiple stages of offensive operations. Rather than relying on AI only for content generation or research, threat actors are now consistently using it to support reconnaissance, vulnerability discovery, credential theft, malware development, social engineering, and activities following initial compromise. The growing use of automated and agent-based workflows is allowing adversaries to coordinate offensive malicious activities with less manual involvement, potentially increasing the speed, scale, and efficiency of future campaigns.
What’s Notable and Unique
In one observed campaign, threat actors used AI to plan, build, and conduct an automated credential-harvesting operation within just several hours, demonstrating how compromised infrastructure can be rapidly repurposed to support larger-scale malicious activity.
Arete has observed several threat groups using AI-assisted capabilities to facilitate the analysis of data obtained during exfiltration so far this year, including INC Ransom, FulcrumSec, and Settra.
Attackers are also attempting to reproduce proprietary AI capabilities. Large-scale automated prompting campaigns have been used to extract information about the behavior and capabilities of proprietary AI models. The use of numerous accounts and intermediary infrastructure can make these activities more difficult to identify and attribute.
Analyst Comments
AI is increasingly becoming an operational component in the threat landscape rather than simply a tool that improves attacker productivity. By connecting reconnaissance, development, credential operations, and other activities through automated workflows, threat actors can conduct campaigns more quickly and reduce reliance on continuous human input. This trend also impacts security requirements for organizations deploying AI technologies. AI models, development environments, cloud resources, identities, repositories, and automated workflows should increasingly be considered interconnected elements of the enterprise attack surface, and organizations should maintain visibility across these areas and ensure that security controls account for both conventional threats and AI-enabled attack techniques.
Sources
GTIG AI Threat Tracker: From Prompting to Autonomy – The Evolution of Adversarial AI
Article
Top 9 Security Controls for SMBs
In today’s complex cyber threat landscape, small and medium-sized businesses (SMBs) should implement a layered, multi-pronged approach to security. Here are some proven, effective controls to consider:
1. Implement MFA for All Users
Multi-factor authentication (MFA) is an effective and accessible way to protect sensitive data, comply with regulatory standards, and prevent unauthorized access to critical systems. By ensuring that users not only use a password but also a secure token, an organization can significantly reduce phishing attempts, credential stuffing attacks, and ransomware incidents. MFA should be enabled for email, VPN, and critical system access.
2. Update Patch Management Programs
A modern patching program should include policies and mechanisms to manage software updates in a timely manner. Patching efforts should address not just operating system updates, but also commonly utilized software within the environment. An active patching plan aims to reduce the mean time to patch and provide metrics on existing patch efforts. In the event of a high-severity vulnerability, a mature patching program should also be able to identify the risks and exposure for a given set of systems based on the average time to patch. This helps stakeholders make informed decisions when a new exploit is released.
3. Leverage a Properly Managed Endpoint Detection and Response (EDR) Tool
With real-time threat detection and advanced visibility, endpoint detection and response (EDR) solutions can enhance an organization’s ability to detect and investigate potential malicious activity, including ransomware, lateral movement, fileless attacks, and more. Effective management of EDR should include proper configuration, regular agent updates, and established procedures for responding to alerts.
4. Enhance EDR with Frontline Incident Intelligence
While EDR solutions are an important component of a security program, threat actors are continually adapting their techniques to evade detection, and as a result, standard detection methods may not always identify emerging threats or novel attack behaviors. To strengthen protection, organizations can supplement EDR tools with custom detection rules informed by incident response data. These rules can help identify indicators of compromise observed during cyber incidents, providing an additional layer of visibility beyond traditional detections.
Arete Bloktd℠ illustrates this approach by transforming threat intelligence and malware analysis into curated detection rules for EDR tools. Applying frontline intelligence to security tools can result in earlier detection, less investigative burden, and a more confident response.
5. Create and Continuously Test an Incident Response (IR) Plan
An incident response plan can help an organization effectively identify, respond to, and recover from a cybersecurity incident while minimizing disruption and downtime. An IR plan defines clear roles, escalation paths, communication strategies, and decision frameworks for both internal and external teams. To be effective, these plans should be regularly tested with post-incident reviews or tabletop exercises involving key stakeholders.
6. Maintain Encrypted and Tested Data Backups
In the case of a cyberattack, backups can help organizations maintain business continuity, support ransom negotiations with threat actors, and contribute to a timely and successful recovery. Encrypting backups makes it more difficult for threat actors to access or alter them, and regular testing ensures they remain accessible during a security incident.
7. Conduct Employee Security Awareness Training
Human error is a leading cause of cybersecurity incidents, and an organization’s employees are its first line of defense against cyber threats. Security awareness training reinforces the importance of data confidentiality, supports regulatory compliance, and helps employees recognize and understand red flags such as suspicious emails, malicious links, and social engineering attempts.
8. Assess and Address Existing Risk and Vulnerabilities
To maintain a proactive approach to risk management and improve resilience, organizations should regularly assess existing vulnerabilities through expert-led Vulnerability Assessments, Penetration Testing, and Threat Hunting Assessments. These exercises can help identify security gaps, support regulatory compliance, and prevent potential incidents. During remediation, prioritize high-impact vulnerabilities and make a plan for periodic assessments.
9. Apply Least-Privilege Access Controls
Employees should have access only to the systems, applications, and data necessary to perform their jobs. By removing unnecessary administrative privileges and regularly reviewing user permissions, organizations can reduce the risk of unauthorized access and limit the damage caused by compromised accounts or insider threats.
Organizations should regularly review their cybersecurity programs, stay informed about emerging threats, and evaluate whether their security controls are adapting to the evolving threat landscape.



