String Patching by CrACKsMAN

Post date: Feb 7, 2011 8:26:22 PM

This delphi snippet, written by one of my best friends CrACKsMAN, details string patching; a simple method to add settings to an executable.

StringPatch.exe

program StringPatch;

//CrACKsMAN

//opensc.ws

uses

  Windows;

function Patch(Path, NewString, OldString: AnsiString): Boolean;

var

  Handle        : THandle;

  BRead, BWrote : Cardinal;

  Size, Offset  : Cardinal;

  FileBuffer    : AnsiString;

begin

  Result := False;

  Handle := CreateFileA(PAnsiChar(Path), GENERIC_WRITE or GENERIC_READ, FILE_SHARE_WRITE or FILE_SHARE_READ, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

  if Handle <> INVALID_HANDLE_VALUE then

  begin

    Size := GetFileSize(Handle, nil);

    SetLength(FileBuffer, Size);

    SetFilePointer(Handle, 0, nil, FILE_BEGIN);

    ReadFile(Handle, PAnsiChar(FileBuffer)^, Size, BRead, nil);

    Offset := Pos(OldString, FileBuffer);

    if Offset <> 0 then

    begin

      SetFilePointer(Handle, Offset -1, nil, FILE_BEGIN);

      WriteFile(Handle, PAnsiChar(NewString)^, Length(OldString), BWrote, nil);

      If Integer(BWrote) = Length(OldString) then

        Result := True;

    end;

  end;

  CloseHandle(Handle);

end;

begin

  Patch('Test.exe',

        'CrACKsMAN patched this string :)',

        '##################################################');

end.

Test.exe

program Test;

uses

  Windows;

var

  Note : AnsiString = '##################################################';

begin

  MessageBoxA(0, PAnsiChar(Note), 'StringPatch', 0);

end.