EDRStartupHinder, a tool released on 2026-01-11 by researcher Two Seven One Three, disables antivirus and Endpoint Detection and Response (EDR) protections during Windows 11 25H2 startup.
Tool Mechanics and Impact
The tool exploits the Windows Bindlink API and Protected Process Light (PPL) protections. By creating a malicious service with high startup priority, it redirects critical System32 DLLs using Bindlink to attacker-controlled locations. This involves modifying a single PE header byte, causing PPL-protected processes to reject unsigned DLLs and terminate.
Laboratory testing demonstrated EDRStartupHinder preventing launch of Windows Defender and other commercial EDR/AV products, although specific products remain unnamed. The tool's ability to hinder vital security processes could impact system protection significantly.
Mitigation and Response Recommendations
The researcher suggests several detection and mitigation strategies: monitor bindlink.dll activity, observe unauthorized Windows service additions, and track service-group registry changes. Establishing baseline monitoring for registry/service startup configurations and implementing comprehensive defense mechanisms can help counter these exploits.
Microsoft has yet to release an official response regarding the vulnerabilities exploited by EDRStartupHinder. The situation underscores the importance of proactive security measures as reliance on Windows 11 grows globally.
