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Threat Actors Continue to Leverage BYOVD Technique

Arete Analysis

Cyber Threats

Multiple ransomware operations have recently been observed leveraging the Bring Your Own Vulnerable Driver (BYOVD) technique to disable endpoint security controls prior to ransomware deployment. Notably, the Qilin ransomware group commonly leverages a malicious msimg32.dll file loaded via DLL side-loading, along with vulnerable drivers including rwdrv.sys and hlpdrv.sys, to gain kernel-level access and disable security processes. Similarly, Warlock ransomware has been observed exploiting the vulnerable NSecKrnl.sys driver to bypass security controls. The use of BYOVD has also been observed across ransomware campaigns associated with Akira, INC, Medusa, and other threat actors. 

What’s Notable and Unique 

  • The Qilin ransomware group employs a sophisticated multi-stage infection chain, leveraging DLL side-loading (msimg32.dll) to execute malicious payloads directly in memory and evade traditional file-based detection. In DLL side-loading, a threat actor tricks a program into loading a malicious dynamic link library. The malware escalates privileges and uses signed but vulnerable drivers (rwdrv.sys and hlpdrv.sys) to bypass security controls, access system memory, and systematically disable endpoint defenses by terminating security processes and disabling monitoring callbacks at the kernel level. 

  • Akira ransomware operators have also exploited the rwdrv.sys and hlpdrv.sys drivers. Additionally, Arete has observed threat actors leveraging multiple other drivers, including the vulnerable TrueSight.sys, to bypass security controls. 

  • Meanwhile, Warlock ransomware operators disguised malicious activity by renaming rclone.exe to TrendSecurity.exe to appear legitimate. The file functioned as a loader, exploiting the vulnerable NSecKrnl.sys driver to disable security processes, while Group Policy Objects (GPOs) were leveraged to systematically disable security controls across the environment. 

Analyst Comments 

The BYOVD technique, employed by multiple known ransomware operators, reflects a broader shift toward pre-encryption defense evasion, including suppression of Windows telemetry, removal of monitoring callbacks, and abuse of legitimately signed but vulnerable drivers. This technique enables threat actors to evade detection, maintain persistence for extended periods, and maximize the operational impact of ransomware deployment across compromised environments. Organizations should implement strict driver control policies, such as Microsoft’s Vulnerable Driver Blocklist and application control mechanisms. Additionally, enforcing least privilege access, enabling multi-factor authentication (MFA), maintaining up-to-date patching, and continuously monitoring for anomalous driver and kernel-level activity can further reduce the risk of such attacks. 

Sources 

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Threat Actors Leverage AI for EDR Evasion

A threat actor has developed and deployed a ransomware attack toolkit enhanced with AI-assisted development workflows, enabling automated Active Directory (AD) discovery and improved EDR evasion capabilities. The toolkit leverages agent-based AI systems, such as Claude’s Opus and Cursor agents, for iterative malware development, testing, and refinement. 

What’s Notable and Unique 

  • Researchers have highlighted that this toolkit can not only generate ransomware code but also bypass sophisticated security defenses and identify AD networks for malware distribution. 

  • The framework incorporates multiple capabilities, including automated AD discovery and reconnaissance mechanisms, iterative EDR testing environments to refine evasion techniques, and a command-and-control (C2) infrastructure that leverages Telegram APIs and Cloudflare redirectors for stealth. 

  • Additionally, some agents were tasked with checking security research and technical posts for various bypass techniques. The agents recognized what was required for reproduction, extracted the techniques, mapped them to the MITRE ATT&CK knowledge base of adversary behaviors, set up a test lab, carried out the methodology, and reported the results. 

  • After a few repetitions, the modules seemed to avoid nearly all EDR solutions, despite the agent’s initial suggestion of a high failure rate. Although researchers found no evidence that AI was embedded in deployed malware or was operating independently in victim environments, the technology was still used to accelerate the iterative process of developing, testing, and refining payloads against security products, shortening the period between the publication of offensive security research and its practical implementation by threat actors. 

Analyst Comments 

AI-driven tools like this could accelerate the pace and sophistication of ransomware attacks, enabling even relatively inexperienced actors to launch high-impact campaigns. This development underscores the urgent need for security solutions to adapt to AI-assisted threats. Organizations must respond by strengthening detection engineering, improving visibility across environments, and maintaining robust security fundamentals.  

Sources 

  • AI-built ransomware toolkit automates EDR evasion, AD discovery  

  • Pointing a Cursor at evading detection

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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.

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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