Contains all the material from the DEF CON 31 workshop "(In)direct Syscalls: A Journey from High to Low".
The following two code samples can be used to understand the difference between direct syscalls and indirect syscalls
Malleable shellcode loader written in C and Assembly utilizing direct or indirect syscalls for evading EDR hooks
shellcode loader that uses indirect syscalls written in D Lang The loader bypasses user-mode hooks by resolving system calls manually from NTDLL using a hash-based method.