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Elastic Security Labs warned that ransomware operators increasingly use legitimately signed but vulnerable Windows drivers to gain kernel-mode execution, tamper with endpoint defenses, and encrypt systems. The researchers identified an unrestricted handle-duplication flaw in the Microsoft Sysinternals Process Explorer driver that a user-mode attacker could exploit to access raw physical memory, enabling arbitrary kernel read/write operations or kernel code execution.
Organizations should treat vulnerable signed drivers as a high-risk attack path and block known-abused drivers before they load. Elastic recommends combining vulnerable-driver blocklists, Windows Defender Application Control (WDAC) driver allowlisting, behavioral protections, and monitoring for first-seen or anomalous driver loads; Elastic Endpoint 8.3 and later validates drivers against its blocklist prior to loading.
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Elastic disclosed that Process Explorer's driver can duplicate a raw physical-memory handle from the Windows System process, enabling arbitrary kernel memory read/write primitives and potentially kernel code execution.
Elastic Security released 65 community-available YARA rules intended to detect abuse of vulnerable Windows drivers, a technique used by ransomware operators to obtain kernel-mode execution and disable security products.
Elastic reported the unrestricted handle-duplication vulnerability in Microsoft Process Explorer's driver through Microsoft's vulnerable-driver submission portal on July 26. Elastic said it had not received a response at the time of writing.
Microsoft had previously blocked the ProcessHacker (now System Informer) driver because of the same unrestricted handle-duplication flaw described in the Process Explorer driver.
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Elastic Security Labs disclosed two Windows zero-day exploit paths that enable attackers with local administrator privileges to bypass Protected Process Light (PPL) protections and escalate from PPL to kernel-level execution. The `PPLFault` and `GodFault` techniques can disable Windows Defender and other AV/EDR controls without a bring-your-own-vulnerable-driver (BYOVD) component, undermining controls intended to restrict administrator-driven kernel tampering. The techniques operate despite Windows defenses including Driver Signing Enforcement, Secure Boot, and the Vulnerable Driver Blocklist, which limit untrusted kernel drivers but do not prevent this driverless exploit chain. Microsoft reportedly declined to patch the issues because exploitation requires administrator access; Elastic released the NoFault kernel driver as an interim PPL mitigation and integrated protection into Elastic Endpoint/Defend version 8.9.0 and later, while the underlying kernel escalation remained unpatched.
Aug 26, 2026
Researchers and threat intelligence sources detailed multiple signed Windows kernel drivers being abused to gain stealthy, high-privilege access and disable defenses. Nextron Systems analyzed `wskmon.sys`, a WHQL-signed Windows Filtering Platform driver that acts as a kernel-resident network backdoor by intercepting inbound TCP traffic and accepting encrypted, HMAC-authenticated commands marked with the magic bytes `7F 4E 54 46`. The malware reportedly enables remote shell execution, arbitrary file writes, and shellcode execution directly from kernel context, allowing it to operate on Secure Boot systems while leaving few user-mode artifacts. Separate LOLDrivers entries highlighted two additional signed drivers tied to ESET’s reporting on Gentlemen ransomware activity: Qihoo’s `360netmon_wfp.sys`, tracked as `Win64/VulnDriver.Qihoo360.A`, and IObit Malware Fighter’s `IMFForceDelete.sys`, associated with `CVE-2019-6494`. The first can be abused to impair endpoint protections and support EDR-killing activity, while the second can be loaded to delete protected files regardless of access controls via `IOCTL 0x8016E000`. Across the reports, defenders were urged to block these drivers, monitor for suspicious signed driver loads and unexpected WFP callout registration, and hunt for indicators such as anomalous `svchost.exe` child processes, kernel-originated file overwrites, and protocol markers in network traffic.
Jun 29, 2026
Researchers and incident responders reported continued abuse of **Bring Your Own Vulnerable Driver (BYOVD)** techniques to disable endpoint protections, including **CrowdStrike Falcon**, by loading legitimately signed but flawed Windows kernel drivers. One newly analyzed zero-day driver family included more than 15 variants with valid Microsoft signatures and an IOCTL path such as `0x22E010` that accepted a process ID and invoked `ZwOpenProcess` and `ZwTerminateProcess` from kernel mode, allowing attackers to kill protected security processes without alerts. A proof-of-concept dubbed **PoisonKiller** demonstrated successful termination of the CrowdStrike EDR process through the driver’s symbolic link, underscoring the risk created by trusted but unrevoked third-party drivers. Separate reporting from Sophos and industry coverage tied the same broader tactic to real intrusions and ransomware activity, including ongoing abuse of **Terminator** and related tools built around vulnerable **Zemana** drivers. Attackers used IOCTL flaws to place their own processes on allow lists and then terminate AV and EDR components, while some incidents showed operators switching to alternatives such as **AuKill** when initial attempts failed. Defenders were urged to combine tamper protection, strict privilege controls, patching, and aggressive blocklisting of unnecessary vulnerable drivers, as signed-driver abuse has spread from advanced actors to commodity ransomware crews and lower-tier criminals.
Jun 30, 2026