security mechanisms

Winsage
March 12, 2026
In March, Microsoft released cumulative security updates for Windows 10 and Windows 11, with support for certain versions continuing until March 2026. The updates include KB5079466 for Windows 11 version 26H1, KB5079473 for versions 24H2 and 25H2, KB5078883 for version 23H2, and KB5078885 for Windows 10 version 22H2. These updates will be distributed via Windows Update, the Microsoft Update Catalog, and WSUS for enterprise environments. This month, Microsoft combined the Servicing Stack Update (SSU) with the Latest Cumulative Update, simplifying the update process. Key enhancements include improvements to Secure Boot, with expanded device target data for new certificates, and security enhancements for Explorer’s search functionality in Windows 11 versions 24H2 and 25H2. A fix for Windows Defender Application Control (WDAC) was also implemented, addressing issues with COM objects under certain policy configurations. The Windows System Image Manager received a new warning dialog for confirming the trustworthiness of catalog files, which is important for enterprise environments. Updates for Windows 10 22H2, despite its end-of-life status, included fixes for secure boot issues and improvements for file version history in the Control Panel. An SSU for Windows 11 (KB5077869) was also released to maintain update stability. Microsoft's updates scheduled for March 2026 will address vulnerabilities in components like the Windows App Installer, SQL Server, and Microsoft Office. The Security Update Guide provides detailed information on specific vulnerabilities and affected components.
Winsage
January 12, 2026
A new tool named EDRStartupHinder was unveiled on January 11, 2026, which allows attackers to inhibit the launch of antivirus and endpoint detection and response (EDR) solutions during the Windows startup process. Developed by security researcher Two Seven One Three, it targets Windows Defender and various commercial security products on Windows 11 25H2 systems by redirecting essential system DLLs during boot using the Windows Bindlink API and Protected Process Light (PPL) security mechanisms. The tool employs a four-step attack chain that includes creating a malicious service with higher priority than the targeted security services, redirecting critical DLLs to attacker-controlled locations, and modifying a byte in the PE header of the DLLs to cause PPL-protected processes to refuse loading them. This results in the termination of the security software. EDRStartupHinder has been tested successfully against Windows Defender and other unnamed antivirus products, demonstrating its effectiveness in preventing these security solutions from launching. The source code for EDRStartupHinder is publicly available on GitHub, raising concerns about its potential misuse. Security teams are advised to monitor for Bindlink activity, unauthorized service creation, and registry modifications related to service groups and startup configurations to detect this attack vector. Microsoft has not yet issued any statements regarding patches or mitigations for this technique.
Tech Optimizer
May 19, 2025
A researcher known as es3n1n explored Windows security mechanisms to bypass antivirus software validation checks in the Windows Security Center (WSC). He used tools like dnSpy and Process Monitor to analyze how legitimate antivirus solutions register with WSC. He confirmed that WSC validates the signatures of processes calling its APIs. Previously, es3n1n faced controversy when his project, no-defender, was removed from GitHub due to a DMCA takedown request from a software vendor.
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