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Operation Bypass: Catch My Payload If You Can

Matthew Eidelberg

Matthew Eidelberg breaks down the mechanics of modern EDR evasion, demonstrating API unhooking, AMSI bypasses, and indirect system calls in offensive payloads.

Summary

The Mechanics of Endpoint Detection and Response (EDR)

Modern EDR agents monitor process execution by injecting user-mode DLLs, hooking Win32 APIs, and subscribing to Event Tracing for Windows (ETW) and AMSI telemetry.

Bypassing User-Mode API Hooks and AMSI

Matthew Eidelberg walks through advanced payload evasion techniques, including patching Antimalware Scan Interface (AMSI) buffers and unhooking loaded ntdll.dll modules.

Implementing Direct and Indirect System Calls

By invoking direct and indirect system calls (Syswhispers/Hell's Gate), offensive payloads bypass userland API hooks entirely, communicating directly with the Windows kernel.

Defensive Engineering and Kernel-Level Visibility

Eidelberg advises defensive teams on relying on kernel-level telemetry (ETW Threat Intelligence, kernel callbacks) rather than fragile user-mode hooks.

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