The Reveal Platform
Intel Name: Reynolds ransomware: byovd abuse of nseckrnl.sys (cve-2025-68947) for kernel-level defense evasion
Date of Scan: February 25, 2026
Impact: High
Summary: The cybersecurity landscape is witnessing a dangerous escalation in how attackers bypass enterprise security controls. Recently, security researchers identified a sophisticated campaign involving Reynolds ransomware, a threat actor focused on high-stakes financial extortion. This group has moved beyond standard malware delivery to adopt a highly technical tactic known as Bring Your Own Vulnerable Driver (BYOVD). By exploiting a specific flaw in a legitimate system file, they effectively silence security software before it has a chance to alert your team. For executive leaders, understanding the reynolds ransomware threat is critical because it represents a move toward disabling the digital immune system of the organization. This strategy makes traditional defenses almost invisible to the breach as it unfolds.
The primary actor behind this campaign, the Reynolds ransomware group, is motivated almost exclusively by financial gain. Unlike state-sponsored groups that may prioritize long-term espionage or intellectual property theft, Reynolds seeks to maximize pressure on a business to pay a heavy ransom. They achieve this by ensuring that their encryption process is fast, comprehensive, and uninterrupted.
To ensure success, they have integrated the abuse of a legitimate but vulnerable signed system driver (identified in reporting as nseckrnl.sys). This choice of target is strategic. Because the driver is a legitimate component, it carries a digital signature that makes it appear trustworthy to the operating system. The Reynolds group uses this trust to gain a foothold in the most protected part of the computer: the kernel. Once they have this level of access, their primary goal is to strip away the organization’s visibility. This leaves the business blind to the impending disaster.
For a CISO or an executive stakeholder, the impact of a Reynolds ransomware attack goes far beyond the cost of a decryption key. This threat is designed to cause total operational disruption. By disabling security tools at the kernel level, the attackers can move laterally through the network with impunity. This allows them to identify and encrypt the most critical business servers, including backups and databases that are essential for daily operations.
Beyond the immediate technical failure, the business faces significant secondary risks. The threat of data exfiltration creates a massive liability for regulatory non-compliance and legal action. Furthermore, the public disclosure of a successful ransomware attack can lead to a long-lasting loss of customer trust and a decline in shareholder value. When an organization cannot operate for days or weeks, the financial losses from downtime often dwarf the actual ransom demand.
To understand how reynolds ransomware functions, imagine your office building has a highly sophisticated security system with cameras and guards. However, there is a specific maintenance worker who has a master key and is trusted by everyone. The attackers do not try to break the windows. Instead, they find a way to trick that trusted maintenance worker into letting them in. Once inside, they use the worker’s authority to turn off the cameras and tell the guards to go home for the night.
In technical terms, the attackers bring a legitimate but flawed driver onto a target machine. Because this driver has a valid signature, the operating system allows it to run with the highest possible privileges. The malware then exploits a publicly reported vulnerability in that driver (tracked under CVE-2025-68947) to execute malicious code. From this vantage point, the ransomware can simply kill the processes belonging to antivirus and EDR tools. Since the security tools are being shut down from a level of authority higher than their own, they cannot defend themselves. According to public threat research, this technique has been observed in active ransomware campaigns where attackers prioritize disabling endpoint defenses before encryption.
Traditional signature-based security controls may struggle against Reynolds ransomware because they primarily rely on recognizing known malicious files. If the file being used is a legitimate system driver, those tools may simply look the other way. Gurucul takes a different approach by focusing on behavior and identity risk. We do not just look at what a file is. We look at what it is doing and who is behind the action.
Our platform utilizes advanced behavioral analytics to monitor the relationship between users, processes, and the system kernel. If a process suddenly attempts to load an old or known-vulnerable driver, Gurucul identifies this as a high-risk anomaly. Even if the driver is legally signed, the context of its deployment triggers an immediate alert. This provides the visibility that attackers try so hard to extinguish.
Gurucul’s Next-Generation SIEM, powered by the REVEAL platform, is designed to defend against tactics such as this BYOVD-based attack. This solution integrates User and Entity Behavior Analytics (UEBA) with technical threat intelligence to create a proactive defense against kernel-level evasion. By correlating endpoint events with network traffic and identity data, Gurucul can spot the early stages of a BYOVD attack before the ransomware has the chance to disable protections.
Gurucul REVEAL does not just wait for an alert from an EDR tool. It monitors the health and activity of the security tools themselves. If an EDR agent suddenly stops communicating, Gurucul’s automated response playbooks can immediately isolate those endpoints. This ensures that even if an attacker manages to blind a local security tool, the broader enterprise defense remains alert and capable of stopping the threat.
For a full technical breakdown of the indicators of compromise and specific detection logic, please visit the Gurucul Community.
