Reynolds ransomware represents an evolution in ransomware tactics by embedding a Bring Your Own Vulnerable Driver (BYOVD) component directly within its payload. BYOVD is an adversarial technique where attackers leverage legitimate but flawed kernel-mode drivers to escalate privileges and disable security software, particularly Endpoint Detection and Response (EDR) tools. In this case, Reynolds drops the vulnerable NsecSoft NSecKrnl driver, which contains a known security flaw (CVE-2025-68947, CVSS 5.7) that allows arbitrary process termination. This driver is used to terminate processes associated with multiple leading security products, including Avast, CrowdStrike Falcon, Palo Alto Networks Cortex XDR, Sophos, and Symantec Endpoint Protection. Unlike traditional BYOVD attacks where the vulnerable driver is deployed separately before ransomware execution, Reynolds bundles the driver with the ransomware itself, making the attack quieter and harder to detect. This bundling eliminates the need for separate deployment steps, reducing the attack surface for defenders to intercept. The tactic has precedent in ransomware families like Ryuk and Obscura. The campaign also features suspicious side-loaded loaders and deployment of remote access tools (GotoHTTP) to maintain persistence post-infection. The use of legitimate signed drivers reduces detection likelihood by security software, as these drivers are trusted by the operating system. The attack chain demonstrates a sophisticated approach to defense evasion, combining privilege escalation, process termination, and ransomware encryption in a single payload. This integration complicates incident response and remediation efforts. The campaign reflects broader ransomware trends, including increased professionalization, use of legitimate infrastructure for delivery, and targeting of cloud environments. The Reynolds ransomware’s ability to disable multiple EDR solutions simultaneously increases its potential impact and operational success.

European organizations are at significant risk from Reynolds ransomware due to the widespread deployment of affected EDR and endpoint security products across the continent. By disabling these security tools, the ransomware can operate undetected, increasing the likelihood of successful encryption of critical data and disruption of business operations. The ability to terminate processes from multiple major security vendors simultaneously means that organizations relying on these solutions may experience complete security blind spots during an attack. This can lead to extended dwell times, increased data loss, and higher ransom payments. Critical infrastructure sectors, including finance, healthcare, manufacturing, and government, are particularly vulnerable given their reliance on endpoint protection and the high value of their data. The embedded BYOVD technique also complicates forensic investigations and incident response, as the attack leaves fewer external indicators. Additionally, the presence of remote access tools post-infection suggests attackers may maintain persistence for further exploitation or data exfiltration. The campaign’s stealth and sophistication could lead to increased ransomware incidents in Europe, with potential cascading effects on supply chains and service availability. The medium severity of the driver vulnerability combined with the ransomware’s capabilities elevates the overall threat level, potentially causing significant operational and financial damage.

1. Implement strict driver control policies using Windows Defender Application Control (WDAC) or similar technologies to whitelist only approved and verified drivers, blocking the loading of vulnerable or unsigned drivers like NSecKrnl. 2. Employ advanced endpoint detection solutions capable of monitoring kernel-mode driver behavior and detecting anomalous process termination attempts, especially those targeting security software processes. 3. Conduct regular threat hunting exercises focused on identifying side-loaded loaders, suspicious driver installations, and unusual process terminations indicative of BYOVD activity. 4. Maintain up-to-date inventories of all installed drivers and promptly apply patches or remove known vulnerable drivers such as those affected by CVE-2025-68947. 5. Use behavioral analytics to detect the presence of remote access tools like GotoHTTP and unusual lateral movement or persistence mechanisms. 6. Segment networks to limit ransomware propagation and restrict administrative privileges to minimize the impact of privilege escalation via vulnerable drivers. 7. Enhance logging and monitoring of driver loading events and process terminations to enable rapid detection and response. 8. Educate security teams on the evolving BYOVD techniques and incorporate detection signatures for known vulnerable drivers and associated attack patterns. 9. Collaborate with endpoint security vendors to ensure their products can detect and mitigate BYOVD-based attacks effectively. 10. Prepare incident response plans specifically addressing ransomware with embedded defense evasion components to reduce response times and impact.