Hello. I recently started reading about anti debug, found great reference with tons of great ideas, but i cant get one to work.

 

http://anti-reversing.com/Downloads/Anti-Reversing/The_Ultimate_Anti-Reversing_Reference.pdf

 

The one i want to try is "Instruction counting", page 30. Most of them work simply by copying asm code int __declspec(naked) but this oen is different, and i couldnt get it to work this way, and i dont have experience in using structured exceptin handlers.

Could someone try to rewrite this small piece of code? Please?

 

Thanks in advance

Another similar example by Waleed Assar can be used as base to code your snippet.

http://waleedassar.blogspot.com/2012/11/ollydbg-raiseexception-bug.html

//http://waleedassar.blogspot.com

//http://www.twitter.com/waleedassar

//In OllyDbg, upon receiving an EXCEPTION_BREAKPOINT, it checks code in ExceptionAddress to ensure it is

//0xCC or similar. If it is not, the behavior depends on the OllyDbg version.

//In versions prior to 2.01, the exception is swallowed and the exception handler is not called.

//In version 2.01 (alpha 4), several error messages pop up and process terminates.

// Only version 2.01 (beta 2) handles it properly.

//The following is code that exploits this bug to detect the presence of OllyDbg.

#include "stdafx.h"

#include "windows.h"

#include "stdio.h"
int __cdecl Hhandler(EXCEPTION_RECORD* pRec,void*,unsigned char* pContext,void*)

{

        if(pRec->ExceptionCode==EXCEPTION_BREAKPOINT)

        {

                (*(unsigned long*)(pContext+0xB8))++;

                MessageBox(0,"Expected","waliedassar",0);

                ExitProcess(0);

        }

        return ExceptionContinueSearch;

}

void main()

{

        __asm

        {

                push offset Hhandler

                push dword ptr fs:[0x0]

                mov dword ptr fs:[0x0],esp

        }

        RaiseException(EXCEPTION_BREAKPOINT,0,1,0);

        __asm

        {

                pop dword ptr fs:[0x0]

                pop eax

        }

        MessageBox(0,"OllyDbg Detected","waliedassar",0);

}