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)
Back to Blog Posts
Article
Arete's 2026 Q1 Crimeware Report
Harness Arete’s unique data and expertise on extortion and ransomware to inform your response to the evolving threat landscape.
Article
CMS Vulnerability Leads to ClickFix Campaign
Threat actors compromised at least 700 education and technology websites in a recent ClickFix campaign by exploiting a critical SQL injection flaw (CVE-2026-26980) in the Ghost content management system (CMS). Adversaries combined the vulnerability with the ClickFix social engineering tactic to steal admin keys and inject a malicious JavaScript that delivers a fake Cloudflare or CAPTCHA verification pop-up, tricking victims into copying and pasting a malicious command into their systems.
What’s Notable and Unique
Rather than targeting the end user first, this campaign is unique in its initial exploitation of the system, followed by social engineering attempts. This hybrid attack style is likely being leveraged to bypass traditional defenses.
This recent campaign also highlights how trusted web properties can be weaponized at scale and coupled with unpatched CMS vulnerabilities. Rather than using the CMS compromise to perpetrate a single attack, threat actors turned it into a supply-chain attack that ultimately affected over 700 trusted websites.
Analyst Comments
As network defenders and their tools enhance threat detection capabilities, adversaries increasingly seek methods to bypass these defenses. By combining vulnerability exploitation, social engineering techniques, and staging for ancillary attacks, this campaign successfully bypassed traditional defenses and inflicted significant impact. Defending against hybrid cyberattacks requires comprehensive security controls beyond simply patching vulnerabilities. Organizations should focus on limiting movement within the environment, detecting abuse of trusted applications, and preventing end-user manipulation.
Sources
700+ education and tech websites hijacked in huge ClickFix malware campaign
Under the engineering hood: Why Malwarebytes chose WordPress as its CMS
Think before you Click(Fix): Analyzing the ClickFix social engineering technique
Ghost CMS Vulnerability Exploited to Infect 700 Sites With ClickFix Malware
Article
Threat Actors Leverage Fake JPEG Files for Initial Access
In a recent campaign, researchers observed threat actors using fake JPEG image files as a delivery mechanism to initiate the deployment of additional malicious components. The false JPEG files are typically distributed via phishing emails or other social engineering-based lures, and are actually PowerShell-based malware that deploys a trojanized version of ConnectWise ScreenConnect to establish and maintain persistence in the compromised environment.
What’s Notable and Unique
This campaign leverages JPEG images as the initial lure, where the images are not merely decoys but part of the infection workflow. Victims are typically led to download or open an image that triggers hidden execution logic or redirects them to a payload-delivery sequence that initiates later stages of the intrusion chain.
The attack chain is designed to blend into legitimate environments, making detection more difficult. Execution typically relies on scripted or native Windows components, often including PowerShell or other living-off-the-land binaries, enabling fileless or near-fileless execution and reducing forensic artifacts on disk.
The multistage design ensures that the initial JPEG does not directly contain the full payload but instead triggers retrieval or decryption steps that progressively assemble the final malicious components in memory.
Analyst Comments
This campaign illustrates how threat actors continue to blur the line between legitimate file handling and malicious execution chains, indicating potential overlap with remote management or administrative tooling. The use of JPEG-based staging combined with script-based execution reflects a broader evolution toward a stealth-first intrusion design, in which file formats serve as triggers rather than payload containers.
Sources
OPERATION SILENTCANVAS : JPEG BASED MULTISTAGE POWERSHELL INTRUSION
Podcast
Cyber Risk and Insurance for Law Firms
In this episode of Bytes of Insight, host Vinny Sakore is joined by Laura Zaroski, Managing Director of the Law Firms Group at Gallagher, as they discuss the evolution of cyber risk for law firms. Tune in for firsthand insights on how to select the right cyber policy, the incident response process, and the nuances of ransom payments and sensitive data.