Executive Summary
In April 2026, cybersecurity researchers from Cisco Talos and Trend Micro identified that the Qilin and Warlock ransomware groups are employing the 'Bring Your Own Vulnerable Driver' (BYOVD) technique to disable endpoint detection and response (EDR) tools on compromised systems. This method involves deploying malicious DLLs, such as 'msimg32.dll,' to initiate multi-stage infection chains that terminate over 300 EDR drivers from various security vendors. By leveraging vulnerable drivers like 'rwdrv.sys' and 'hlpdrv.sys,' these ransomware groups effectively neutralize security defenses, facilitating the encryption of files and demanding ransoms from victims. (thehackernews.com)
The adoption of BYOVD tactics by Qilin and Warlock underscores a significant evolution in ransomware strategies, highlighting the increasing sophistication of threat actors in circumventing traditional security measures. This trend necessitates enhanced vigilance and the implementation of advanced security protocols to detect and mitigate such evasive techniques.
Why This Matters Now
The use of BYOVD techniques by ransomware groups like Qilin and Warlock represents a critical escalation in cyber threats, as it allows attackers to effectively disable security defenses, leading to increased risk of data breaches and operational disruptions. Organizations must urgently reassess and strengthen their security postures to defend against these advanced tactics.
Attack Path Analysis
The Qilin and Warlock ransomware groups initiated attacks by exploiting stolen credentials to gain initial access. They escalated privileges by deploying vulnerable drivers to disable security tools. Utilizing legitimate remote management tools, they moved laterally across the network. Command and control were established through backdoors and remote access utilities. Data exfiltration was conducted using tools like Rclone. Finally, they encrypted critical files and demanded ransom payments.
Kill Chain Progression
Initial Compromise
Description
Attackers gained initial access by exploiting stolen credentials, such as those obtained through phishing or credential reuse.
Related CVEs
CVE-2024-21762
CVSS 9.8An out-of-bounds write vulnerability in Fortinet FortiOS and FortiProxy SSL VPN allows remote code execution.
Affected Products:
Fortinet FortiOS – < 7.0.12, < 7.2.5
Fortinet FortiProxy – < 7.0.12, < 7.2.5
Exploit Status:
exploited in the wildCVE-2024-55591
CVSS 9.8An authentication bypass vulnerability in Fortinet FortiOS allows attackers to gain super-admin privileges.
Affected Products:
Fortinet FortiOS – < 7.0.12, < 7.2.5
Exploit Status:
exploited in the wildCVE-2023-27532
CVSS 7.5A vulnerability in Veeam Backup & Replication allows unauthorized access to backup configurations and credentials.
Affected Products:
Veeam Backup & Replication – < 12.0.0.1420
Exploit Status:
exploited in the wild
MITRE ATT&CK® Techniques
Hijack Execution Flow: DLL Side-Loading
Exploitation for Privilege Escalation
Impair Defenses: Disable or Modify Tools
Exploitation for Defense Evasion
Virtualization/Sandbox Evasion
Data Destruction
Potential Compliance Exposure
Mapping incident impact across multiple compliance frameworks.
PCI DSS 4.0 – Ensure that all system components and software are protected from known vulnerabilities by installing applicable vendor-supplied security patches.
Control ID: 6.2
NYDFS 23 NYCRR 500 – Cybersecurity Policy
Control ID: 500.03
DORA – ICT Risk Management Framework
Control ID: Article 5
CISA ZTMM 2.0 – Device Security
Control ID: 3.1
NIS2 Directive – Cybersecurity Risk Management Measures
Control ID: Article 21
Sector Implications
Industry-specific impact of the vulnerabilities, including operational, regulatory, and cloud security risks.
Health Care / Life Sciences
Qilin ransomware's BYOVD technique disabling EDR tools creates critical patient data exposure risks, violating HIPAA compliance requirements for encryption and access controls.
Financial Services
Warlock ransomware bypassing security controls threatens financial data integrity and regulatory compliance, particularly impacting PCI-DSS requirements for network segmentation and monitoring.
Information Technology/IT
IT infrastructure providers face direct exposure to vulnerable driver exploitation techniques, compromising client security postures and zero trust architecture implementations across environments.
Government Administration
Government systems vulnerable to EDR bypass attacks risk sensitive data exfiltration and operational disruption, requiring enhanced east-west traffic monitoring and segmentation controls.
Sources
- Qilin and Warlock Ransomware Use Vulnerable Drivers to Disable 300+ EDR Toolshttps://thehackernews.com/2026/04/qilin-and-warlock-ransomware-use.htmlVerified
- Qilin Ransomware: Operating Model, Attack Chain, and Technical Profilehttps://www.provendata.com/blog/qilin-ransomware/Verified
- Ransom:Linux/Qilin!rfn threat description - Microsoft Security Intelligencehttps://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=Ransom%3ALinux%2FQilin%21rfnVerified
Frequently Asked Questions
Cloud Native Security Fabric Mitigations and ControlsCNSF
Aviatrix Zero Trust CNSF is pertinent to this incident as it embeds security directly into the cloud fabric, potentially reducing the attacker's ability to move laterally and exfiltrate data.
Control: Cloud Native Security Fabric (CNSF)
Mitigation: While Aviatrix CNSF may not prevent initial access via stolen credentials, it could limit the attacker's ability to exploit this access to move laterally or escalate privileges.
Control: Zero Trust Segmentation
Mitigation: Aviatrix Zero Trust Segmentation could likely limit the attacker's ability to escalate privileges by enforcing strict access controls and segmenting workloads.
Control: East-West Traffic Security
Mitigation: Aviatrix East-West Traffic Security would likely constrain lateral movement by monitoring and controlling internal traffic between workloads.
Control: Multicloud Visibility & Control
Mitigation: Aviatrix Multicloud Visibility & Control could likely reduce the effectiveness of command and control channels by providing comprehensive monitoring and control over network traffic.
Control: Egress Security & Policy Enforcement
Mitigation: Aviatrix Egress Security & Policy Enforcement would likely limit data exfiltration by controlling and monitoring outbound traffic.
While Aviatrix CNSF may not prevent the encryption of files, it could likely reduce the overall impact by limiting the attacker's ability to spread ransomware across segmented workloads.
Impact at a Glance
Affected Business Functions
- Data Management
- IT Operations
- Customer Service
Estimated downtime: 14 days
Estimated loss: $500,000
Potential exposure of sensitive customer data and internal operational information.
Recommended Actions
Key Takeaways & Next Steps
- • Implement Zero Trust Segmentation to restrict lateral movement and limit the spread of ransomware.
- • Enforce Egress Security & Policy Enforcement to monitor and control outbound traffic, preventing data exfiltration.
- • Deploy Inline IPS (Suricata) to detect and block known exploit patterns and malicious payloads.
- • Utilize Multicloud Visibility & Control to gain comprehensive insights into network traffic and detect anomalies.
- • Establish Threat Detection & Anomaly Response mechanisms to identify and respond to suspicious activities promptly.
