IsDebuggerPresent

Created the Monday 18 March 2019. Updated 6 months, 1 week ago.

This function checks specific flag in the Process Environment Block (PEB) for the field IsDebugged which will return zero if the process is not running into a debugger or a nonzero if a debugger is attached.

If you want to understand the underlying process of IsDebuggerPresent API you can check the code snippet section for the following method: IsDebugged Flag.

Technique Identifiers

U0122 B0001.008

Technique Tag

isdebuggerpresent

Featured Windows API's

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IsDebuggerPresent

Code Snippets

#include <windows.h>
#include <stdio.h>

int main(int argc, char** argv)
{
	if (IsDebuggerPresent())
	{
            printf("Debugger detected!!\n");
	}
	else
	{
	    printf("No debugger detected!!\n");
	}
	system("pause");
	return 0;
}

program IsDebuggerPresent;

{$APPTYPE CONSOLE}

uses
  WinAPI.Windows, System.SysUtils;

begin
  try
    if IsDebuggerPresent() then
      WriteLn('Process is currently getting debugged.')
    else
      WriteLn('Process is not likely getting debugged.');

    readln;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.

Detection Rules

                                    rule Detect_IsDebuggerPresent : AntiDebug {
    meta:
        author = "naxonez"
        reference = "https://github.com/naxonez/yaraRules/blob/master/AntiDebugging.yara"
    strings:
	$ ="IsDebugged"
    condition:
        uint16(0) == 0x5A4D and filesize < 1000KB and any of them
}

Additional Resources

External Links

The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.

IsDebuggerPresent function (debugapi.h) - Win32 apps | Microsoft Docs