Windows C++ / Call to Interrupt Procedure by Alex Schwarz
Created the Friday 10 March 2023. Updated 6 months, 1 week ago.
Description:
This code is implementing an anti-debugging technique that checks if a debugger is present in the environment. The TestDebugger() function generates a software interrupt (INT 3) using inline assembly code in x86 architecture.
If a debugger is present, it would intercept this interrupt, and the __except block will not execute, resulting in the TestDebugger() function returning false. On the other hand, if no debugger is present, the __except block will be executed, and the function will return true.
The main() function calls the TestDebugger() function and prints a message indicating whether a debugger was found or not. This code could be used as a security measure to protect against reverse engineering or malicious attacks by detecting if a debugger is present during runtime.
Code
#include <stdio.h>
#include <windows.h>
bool TestDebugger()
{
__try
{
__asm //x86 implementation
{
_emit 0xCD
_emit 0x03 //INT 03
_emit 0xC3 //RET
}
}
__except (EXCEPTION_EXECUTE_HANDLER)
{
return false;
}
return true;
}
int main()
{
if(TestDebugger())
{
printf("Found debugger!\n");
}
}