Peeling Back the Socket Layer: Reverse Engineering Windows AFD.sys

Original text by Mateusz Lewczak

Part 1: Investigating Undocumented Interfaces

The four-part research series explores the reverse engineering of the Windows AFD.sys (Ancillary Function Driver) to understand how networking operations work beneath the Winsock API. AFD.sys is a kernel driver that acts as a bridge between user-mode socket APIs and the lower networking stack, translating…

https://core-jmp.org/2026/03/peeling-back-the-socket-layer-reverse-engineering-windows-afd-sys/