Crack Tutorial by Vizion, 09/97
[TARGET...........]:
SmilerShell/95 v1.4 (url : www.windows95.com)
[TOOLZ............]:
W32Dasm v8.9, SoftIce 3.01
[PROTECTION.......]:
registration key
[REMARK(s)........]:
problably cracked already by some other people
[PRECRACK NOTES...]:
I assume that you have some knowledge about ASM and are able to use W32Dasm and SoftIce
[#1 THe KEY.......]:
Hi again! Today we take a look at SmilerShell/95. When we load the program, we can see that a registration key is all we need to register this target.
First of all create a "dead-listing" with W32Dasm. Why we do that? Well we want to know what .dll calls are made. So goto the next section in W32Dasm,
+++++++++++++++++++ IMPORTED FUNCTIONS ++++++++++++++++++
Number of Imported Modules = 6 (decimal)
Import Module 001: KERNEL32.dll
Import Module 002: USER32.dll <--- interesting
Import Module 003: GDI32.dll
Import Module 004: comdlg32.dll
Import Module 005: ADVAPI32.dll
Import Module 006: SHELL32.dll
So jump to the details about USER32.dll
Import Module 002: USER32.dll
...
Addr:00030F0C hint(00E8) Name: GetDesktopWindow
Addr:00030BF4 hint(00C1) Name: EnumWindows
Addr:00030BE8 hint(015C) Name: IsWindow
Addr:00030BD6 hint(0135) Name: GetWindowTextA <--- interesting
Addr:00030BC4 hint(008A) Name: DialogBoxParamA
Addr:00030BB8 hint(0159) Name: IsIconic
...
Addr:00030AFE hint(01A3) Name: PostMessageA
Addr:00030AEE hint(0207) Name: SetWindowPos
Addr:00030AD8 hint(01C4) Name: SendDlgItemMessageA
Addr:00030AC6 hint(00ED) Name: GetDlgItemTextA <--- interesting
Addr:00030AB8 hint(0188) Name: MessageBoxA
Addr:00030E1C hint(0115) Name: GetParent
...
Ok, we got to choices to set a breakpoint on. Let's start with GetWindowTextA. Start SoftIce (SI) and enter it (Ctrl-D). Set a breakpoint on GetWindowTextA
type : BPX GetWindowTextA
and exit SI (Ctrl-D again), run SmilerShell/95 (SS) and enter any key (I used : 12121212). Bingo! You should be right back in SI, press F11 to get out of the function and disable the breakpoint
type : BD 0
Now you'll see that GetWindowTextA was called from within GetDlgItemTextA. Now press F10 twice to get into the SS-code, if you should have set a breakpoint on GetDlgItemTextA, you would have saved two F10'n (try it). Either way, you should get at the following code,
* Reference To: USER32.GetDlgItemTextA, Ord:00EDh
|
:00401CCA FF15B4064300 Call dword ptr [004306B4]
:00401CD0 85C0 test eax, eax <--- has user entered a key?
:00401CD2 0F841F020000 je 00401EF7 <--- jump if no key
* Possible Reference to String Resource ID=00001: "&Hide!"
|
:00401CD8 C785ACFEFFFF01000000 mov dword ptr [ebp+FFFFFEAC], 00000001
:00401CE2 0FBE85B0FEFFFF movsx eax, byte ptr [ebp+FFFFFEB0]
:00401CE9 50 push eax
:00401CEA E88E9B0100 call 0041B87D <--- upcase first char of key
:00401CEF 83C404 add esp, 00000004
:00401CF2 8885B0FEFFFF mov byte ptr [ebp+FFFFFEB0], al
* Possible Reference to String Resource ID=00001: "&Hide!"
|
:00401CF8 C785A8FEFFFF01000000 mov dword ptr [ebp+FFFFFEA8], 00000001
:00401D02 E906000000 jmp 00401D0D <--- jump to 00401D0D
* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:00401D93(U)
|
:00401D07 FF85A8FEFFFF inc dword ptr [ebp+FFFFFEA8]
* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:00401D02(U)
|
:00401D0D 8B85A8FEFFFF mov eax, dword ptr [ebp+FFFFFEA8]
:00401D13 0FBE8405B0FEFFFF movsx eax, byte ptr [ebp+eax-00000150]
:00401D1B 85C0 test eax, eax
:00401D1D 0F8475000000 je 00401D98
:00401D23 833D64E3420001 cmp dword ptr [0042E364], 00000001
:00401D2A 0F8E24000000 jle 00401D54 <--- jump to 00401D54
...
* Referenced by a (U)nconditional or (C)onditional Jump at Address:
|:00401D2A(C)
|
:00401D54 8B85A8FEFFFF mov eax, dword ptr [ebp+FFFFFEA8]
:00401D5A 0FBE8405B0FEFFFF movsx eax, byte ptr [ebp+eax-00000150]
...
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:00401D1D(C), :00401D8E(U)
|
:00401D98 83BDACFEFFFF00 cmp dword ptr [ebp+FFFFFEAC], 00000000
:00401D9F 0F8422000000 je 00401DC7
:00401DA5 8D85B0FEFFFF lea eax, dword ptr [ebp+FFFFFEB0]
:00401DAB 50 push eax
:00401DAC E87F9A0100 call 0041B830
:00401DB1 83C404 add esp, 00000004
:00401DB4 83F80B cmp eax, 0000000B <--- is lenght of entered key = 11
:00401DB7 0F840A000000 je 00401DC7
:00401DBD C785ACFEFFFF00000000 mov dword ptr [ebp+FFFFFEAC], 00000000
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:00401D9F(C), :00401DB7(C)
|
:00401DC7 83BDACFEFFFF00 cmp dword ptr [ebp+FFFFFEAC], 00000000
:00401DCE 0F841A000000 je 00401DEE
:00401DD4 0FBE85B7FEFFFF movsx eax, byte ptr [ebp+FFFFFEB7] <--- get 8th char
:00401DDB 83F833 cmp eax, 00000033 <--- equal to '3'
:00401DDE 0F840A000000 je 00401DEE
:00401DE4 C785ACFEFFFF00000000 mov dword ptr [ebp+FFFFFEAC], 00000000
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:00401DCE(C), :00401DDE(C)
|
:00401DEE 83BDACFEFFFF00 cmp dword ptr [ebp+FFFFFEAC], 00000000
:00401DF5 0F841A000000 je 00401E15
:00401DFB 0FBE85B4FEFFFF movsx eax, byte ptr [ebp+FFFFFEB4] <--- get 5th char
:00401E02 83F830 cmp eax, 00000030 <--- equal to '0'
:00401E05 0F840A000000 je 00401E15
:00401E0B C785ACFEFFFF00000000 mov dword ptr [ebp+FFFFFEAC], 00000000
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:00401DF5(C), :00401E05(C)
|
:00401E15 83BDACFEFFFF00 cmp dword ptr [ebp+FFFFFEAC], 00000000
:00401E1C 0F841A000000 je 00401E3C
:00401E22 0FBE85B3FEFFFF movsx eax, byte ptr [ebp+FFFFFEB3] <--- get 4th char
:00401E29 83F834 cmp eax, 00000034 <--- equal to '4'
:00401E2C 0F840A000000 je 00401E3C
:00401E32 C785ACFEFFFF00000000 mov dword ptr [ebp+FFFFFEAC], 00000000
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:00401E1C(C), :00401E2C(C)
|
:00401E3C 83BDACFEFFFF00 cmp dword ptr [ebp+FFFFFEAC], 00000000
:00401E43 0F841A000000 je 00401E63
:00401E49 0FBE85B1FEFFFF movsx eax, byte ptr [ebp+FFFFFEB1] <--- get 2nd char
:00401E50 83F832 cmp eax, 00000032 <--- equal to '2'
:00401E53 0F840A000000 je 00401E63
:00401E59 C785ACFEFFFF00000000 mov dword ptr [ebp+FFFFFEAC], 00000000
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:00401E43(C), :00401E53(C)
|
:00401E63 83BDACFEFFFF00 cmp dword ptr [ebp+FFFFFEAC], 00000000
:00401E6A 0F841A000000 je 00401E8A
:00401E70 0FBE85B6FEFFFF movsx eax, byte ptr [ebp+FFFFFEB6] <--- get 7th char
:00401E77 83F830 cmp eax, 00000030 <--- equal to '0'
:00401E7A 0F840A000000 je 00401E8A
:00401E80 C785ACFEFFFF00000000 mov dword ptr [ebp+FFFFFEAC], 00000000
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:00401E6A(C), :00401E7A(C)
|
:00401E8A 83BDACFEFFFF00 cmp dword ptr [ebp+FFFFFEAC], 00000000
:00401E91 0F841A000000 je 00401EB1
:00401E97 0FBE85B0FEFFFF movsx eax, byte ptr [ebp+FFFFFEB0] <--- get 1st char
:00401E9E 83F843 cmp eax, 00000043 <--- equal to 'C'
:00401EA1 0F840A000000 je 00401EB1
:00401EA7 C785ACFEFFFF00000000 mov dword ptr [ebp+FFFFFEAC], 00000000
* Referenced by a (U)nconditional or (C)onditional Jump at Addresses:
|:00401E91(C), :00401EA1(C)
|
:00401EB1 83BDACFEFFFF00 cmp dword ptr [ebp+FFFFFEAC], 00000000
:00401EB8 0F8419000000 je 00401ED7
:00401EBE 8D85B0FEFFFF lea eax, dword ptr [ebp+FFFFFEB0]
:00401EC4 50 push eax
:00401EC5 6860434200 push 00424360
:00401ECA E871880100 call 0041A740
:00401ECF 83C408 add esp, 00000008
:00401ED2 E920000000 jmp 00401EF7
...
So from this code we know that the key needs the next format : C2x40x03xxx, and the value for x can be anything from 0-9. Voila, another target has just been cracked.
Now let's go on and create a little key generator for it, so that you can show the whole world how good you are ;).
[#2 KEY GEN.......]:
I will use Borland Pascal 7.0 for this little example, why? Well I think pascal is quite readable, and that's important i think :). Ofcourse you can do this in ASM or C or any programming language you like. Ok, here follows the code for the keygenerator,
-----------------------------------------------------------------------------------
program SmilerShell;
var
key : string;
begin
writeln('SmilerShell/95 v1.4 - Key Generator by Vizion [VC97]');
randomize;
key[0] := #11; <--- set lenght of string at 11
key[1] := char(67); <--- fill string with needed and some random values
key[2] := char(50);
key[3] := char(random(9) + 48);
key[4] := char(52);
key[5] := char(48);
key[6] := char(random(9) + 48);
key[7] := char(48);
key[8] := char(51);
key[9] := char(random(9) + 48);
key[10] := char(random(9) + 48);
key[11] := char(random(9) + 48);
write('Registration key : ', key)
end.
-----------------------------------------------------------------------------------
I think you should be able to understand most of the code.
So that's all. Easy!
[GREETZ...........]:
All people on #cracking4newbies and #cracking, members of Mexelite`97/c4n
Fravia for his (awesome) home page, Razzi, +ORC, and many others for there great tutorials
So that's all folks, hope you enjoyed it and learned something,
Vizion.