Reverse Code Engineering RCE CD +sandman 2000/ReverseCodeEngineeringRceCdsandman2000.iso/RCE/Mendoza/dc_patchers.txt

Text File | 2000-05-25 | 13.1 KB | 371 lines

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| General Tutorial about Patchers |  by da Cracker/CBE
 ---------------------------------


Introduction:
────────────
If you read all my four tutorials (the first doesn't help, I think :( ), you
should know how to crack:
- Basic protections (Hex Workshop)
- A bit harder basic protections (WinRoute Lite)
- Intermediate Protections (Visual Page)

With this knowledge, you should be able to crack about ... 40% of the programs!
Well, now, I'm going to make deaper approach to patchers.
I hope that you'll enjoy the tutorial! If you have any
comment, suggestions, .... please e-mail me at [e-mail]


 ┌──────────Index──────────┐
 |                         |
 |1) C++ Patchers          |
 |2) Turbo Pascal Patchers |
 |3) Assembler Patchers    |
 |4) Windows Patchers      |
 |5) Final Notes           |
 └─────────────────────────┘

1) C++ Patchers
   ────────────

In our days, many programmers use C++ to do their programs... Why? Because
it's a very portable version (ie. Without changing the code, it can work in
Unix, Linux, DOS, Mac, Windows, ...) So if we can do a program in C++, why not
a patcher? Yes, we can, because in C++, there are two functions to open files
as output:

A) ofstream myfile(file.exe, ios::binary);
B) fopen("file.exe", "r+")

The A method needs the file fstream.h to be included (#include <fstream.h>)
The B method needs the file stdio.h to be included (#include <stdio.h>)

But in this tutorial, for C++, we are going to use the method B, because it
also has seek methods (to find the right spot in the exe file)

Ok, now comes the source code commented:

------------------------------------cut here----------------------------------
#include <stdio.h> // File required to make fopen work!

long filesize(FILE *stream) // A function that get the size of the program (to check)
{
   long curpos, length;
   curpos = ftell(stream);
   fseek(stream, 0L, SEEK_END);
   length = ftell(stream);
   fseek(stream, curpos, SEEK_SET);
   return length;
}
main() { // Program start

int   counter;
FILE *filename;
unsigned char readbyte;

long int offset[2] = {
    35345, 35346 };

unsigned char data[4] = {
        116, 144, 17, 144 }; // The first number is the original data from the first offset, the 2nd
                             // number is the modified data; the 3rd data is the original data from
                             // the second offset, the 4th one is the modified data, etc...

printf(" ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄\n"); // \n is a line break
printf("█▀                                   ▀█\n");
printf("█           Visual Page v1.0          █\n"); // Name of the program
printf("█   REMOVES EXPIRATION DATE + NAG     █\n"); // What does it do?
printf("█                                     █\n");
printf("█      E-mail: [e-mail]     █\n"); // Guess what?
printf("█     Website: http://www.cbe98.org   █\n");
printf("█         IRC: #cbe98 on Efnet        █\n"); // Come and chat with us!
printf("█▄                                   ▄█\n");
printf(" ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀\n\n");
printf("■ OPENING FILE : "); // Self explanatory ;)
if ((filename = fopen("VPAGE.EXE", "r+")) == NULL) { // Replace VPAGE.EXE with the exe file of the program
      printf("SUCCESS!\n■ CHECKING SIZE : ");
 if (filesize(filename) == 1266204) { // Replace 1266204 with the exact size of the program (type "dir" in dos)
      printf("SUCCESS!\n■ CRACKING FILE : ");
       for (counter=1;counter<3;counter++) {
          fseek(filename,offset[counter-1],SEEK_SET);
          fscanf(filename,"%c",&readbyte);
      if (readbyte == data[(counter*2)-2]) {
      fseek(filename,offset[counter-1],SEEK_SET);
      fprintf(filename,"%c",data[(counter*2)-1]);
      } else
          {printf("ERROR!\n■ FILE ALREADY PATCHED OR DIFFERENT!\n"); fclose(filename); return 1; }
      }
       printf("SUCCESS!\n■ PATCH SUCCESSFULL!\n");
   } else printf("ERROR!\n■ FILESIZE MISMATCH!\n");
       fclose(filename);
} else printf("ERROR!\n■ CAN'T OPEN FILE!\n");
return 0;
}
--------------------------------cut here--------------------------------------


2) Turbo Pascal Patchers
   ─────────────────────

Turbo Pascal is another language used by programmers... Anyway, here's the
source code for a patcher:

------------------------------------cut here----------------------------------
Const Offset : Array [1..2] Of LongInt = (
    35345, 35346 );

Const Data : Array [1..4] Of Byte = (
    116, 144, 17, 144 );

Var Filename: File;
  Counter : Word;
  Readbyte : Byte;
Begin
  Write (' ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄'+ #13+ #10+);
  Write ('█▀                                   ▀█'+ #13+ #10+);
  Write ('█           Visual Page v1.0          █'+ #13+ #10+);
  Write ('█   REMOVES EXPIRATION DATE + NAG     █'+ #13+ #10+);
  Write ('█                                     █'+ #13+ #10+);
  Write ('█      E-mail: [e-mail]     █'+ #13+ #10+);
  Write ('█     Website: http://www.cbe98.org   █'+ #13+ #10+);
  Write ('█         IRC: #cbe98 on Efnet        █'+ #13+ #10+);
  Write ('█▄                                   ▄█'+ #13+ #10+);
  Write (' ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀'+ #13+ #10+ #13+ #10);
  Write ('■ OPENING FILE : ');
  Assign (Filename, 'VPAGE.EXE');
  {$I-} Reset (Filename, 1); {$I+}
  If IOResult = 0 Then Begin
    Write ('SUCCESS!'+ #13+ #10+ '■ CHECKING SIZE : ');
    If FileSize (Filename) = 1266204 Then Begin
      Write ('OK!'+ #13+ #10+ '■ CRACKING FILE : ');
      For Counter:= 1 To 2 Do Begin
           Seek (Filename, Offset [Counter] );
        BlockRead (Filename, Readbyte, 1);
        If Readbyte = Data [Counter* 2- 1] Then Begin
          Seek (Filename, Offset [Counter] );
          BlockWrite (Filename, Data [Counter* 2], 1);
        End Else Begin
          WriteLn ('ERROR!'+ #13+ #10+ '■ FILE ALREADY PATCHED OR DIFFERENT!'); Close(Filename); Halt;
        End;
      End;
      Close (Filename);
      WriteLn ('OK!'+ #13+ #10+ '■ PATCH SUCCESSFULL!');
    End Else WriteLn ('ERROR!'+ #13+ #10+ '■ WRONG VERSION OF FILE!');
  End Else WriteLn ('ERROR!'+ #13+ #10+ '■ CAN''T OPEN FILE!');
End.
-------------------------------------cut here---------------------------------

3) Assembler Patchers
   ──────────────────

Assembler is a quite hard programming language, because it's a low level one
(right before machine level code)... Well, here's the Assembler source code
for a patcher

-------------------------------------cut here---------------------------------
code            segment byte public
        assume    cs:code, ds:code

        org    100h
start:
                mov     dx,offset logo          ; Shows your logo
                call    write            ; write the message

                call    open_file               ; Guess what ?
        mov    filehandle,ax           ; Put the filehandle in "filehandle"

                mov     dx,offset fsize
                call    write            ; write the message

                call    check_size        ; Check the current filesize

            mov     di,offset data        ; Point di to data table
                mov     si,offset ofs        ; Point si to offset table
        mov    cx,2            ; Loop ???? times
                mov     dx,offset crackfile
                call    write            ; write the message

crackit:
        push    cx            ; Save cx
                call    seek_file         ; Seek in the file
                call    read_file        ; Read one byte and compare
                call    seek_file        ; Seek again (back)
                call    write_file        ; Write the byte

                add     si,4            ; Add 4 to si 2*sizeof(word)
                add     di,2            ; Add 2 to di 2*sizeof(byte)
        pop    cx            ; Bring cx back
        loop    crackit            ; Loop Crackit

                mov     dx,offset cracksucc
                jmp     short goback

already_patched:
                mov     dx,offset alreadycrk
                jmp     short goback

size_mismatch:
                mov     dx,offset sizemismtch
                jmp     short goback

error:
                mov     dx,offset erroropen
goback:
                call    write            ; write the message

                call     close_file        ; Close the file

                mov     ah,4Ch                  ; Jump back to the operating system
                int     21h


Write           proc    near
              push    ax
                mov     ah,9
                int     21h                     ; Display String
            pop    ax
                retn
Write           endp

open_file       proc    near
                mov     ah,3Dh
                mov     al,2                    ; open file function 3Dh
                mov     dx,offset filenaam
                int     21h
                jb      error
                retn
open_file       endp

close_file      proc near
                mov     ah,3Eh                  ; close file function 3Eh
                mov     bx,filehandle
                int     21h
                retn
close_file      endp

check_size      proc near
                mov     bx,ax
                mov     ax,4202h
                xor     cx,cx                   ; Check the filelength
                xor     dx,dx
                int     21h
                jb      error
                cmp     ax, lowsize             ; (Lowbyte)
                jne     size_mismatch
                cmp     dx, highsize            ; (Highbyte)
                jne     size_mismatch
                retn
check_size      endp

read_file       proc near
                mov     ah,3fh
                mov     bx,filehandle           ; read file function 3Fh
                mov     cx,1
                mov     dx,offset readbyte
                int     21h
        mov    ah,readbyte
                cmp     [di],ah                 ; Compare patched bytes
                jne     already_patched
        jb    error
        retn
read_file       endp

write_file      proc near
                mov     ah,40h
                mov     bx,filehandle
                mov     cx,1                    ; write file function 40h
                mov     dx,di
        inc    dx
                int     21h
        jb     error
        retn
write_file      endp

seek_file       proc    near
                mov     ah,42h
                mov     al,0
                mov     bx,filehandle           ; move file ptr function 42h
                mov     dx,[si]
        mov    cx,[si+2]
                int     21h
        jnc     here
                jmp    error
here:
                retn
seek_file       endp


filenaam        db      'VPAGE.EXE', 0
filehandle    dw    0
lowsize         dw      21020
highsize        dw      19
readbyte        db      0

logo            db      ' ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄', 0Dh, 0Ah
                db      '█▀                                   ▀█', 0Dh, 0Ah
                db      '█           Visual Page v1.0          █', 0Dh, 0Ah
                db      '█   REMOVES EXPIRATION DATE + NAG     █', 0Dh, 0Ah
                db      '█                                     █', 0Dh, 0Ah
                db      '█      E-mail: [e-mail]     █', 0Dh, 0Ah
                db      '█     Website: http://www.cbe98.org   █', 0Dh, 0Ah
                db      '█         IRC: #cbe98 on Efnet        █', 0Dh, 0Ah
                db      '█▄                                   ▄█', 0Dh, 0Ah
                db      ' ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀', 0Dh, 0Ah
                db      '■ OPENING FILE : ','$'
fsize           db      'SUCCESS!',0Dh,0Ah,'■ CHECKING FILESIZE : $'
crackfile       db      'SUCCESS!',0Dh,0Ah,'■ CRACKING FILE : $'
cracksucc       db      'SUCCESS!',0Dh,0Ah,'■ PATCH SUCCESSFULL!',0Dh,0Ah,'$'
alreadycrk      db      'ERROR!',0Dh,0Ah,'■ FILE ALREADY PATCHED OR DIFFERENT!',0Dh,0Ah,'$'
sizemismtch     db      'ERROR!',0Dh,0Ah,'■ WRONG VERSION OF FILE!',0Dh,0Ah,'$'
erroropen       db      'ERROR!',0Dh,0Ah,'■ CAN', 027h,'T OPEN FILE!',0Dh,0Ah,'$'

ofs             dw    35345 , 0 , 35346 , 0

data            db    116, 144 , 17, 144

code        ends

        end    start
-------------------------------------cut here---------------------------------

4) Windows Patchers
   ────────────────

Many of you guys probably know how to program in a visual language (ie. Visual
Basic, Delphi, Borland C++ Builder, ...) or even in a non visual language
(Visual C++, they call it visual, hahaha). Well, with these programming
languages, you can do patchers. From these languages, I only know Visual Basic,
so I'm going to tell you how to do a visual basic patcher (even though the
users need the Visual Basic runtimes to make it work... But almost everyone has
them):

A) Start Visual Basic
B) Choose Create a new exe
C) Do your own design
D) Do a button called "Patch it!", or whatever
E) Double-click on this button (shows the source code)
F) Type "Open file.exe For Binary Access Write As #1"
That's the function who opens a file in binary mode for editing! After, you
have to tell the location that needs to be patched, the data, etc... At the
end, to close the file, type "Close #1".


5) Final Notes
   ───────────

If you didn't understand ANYTHING in this tutorial, just use a patcher... It's
MUCH easier. For CBE memberz, you can get a patcher in the directory patchers/
from the memberz ftp area... For the others: search the net ;)

I hope that you enjoyed reading this tutorial as much as I did writing it!
Good luck!

btw, my next cracking tutorial is going to be about ummm, dunno yet... =)

-da Cracker/CBE
[e-mail]
http://www.cbe98.org
#cbe98 on Efnet
Come and chat with us on IRC!