xoanon

The TimeLOCK_DLL cracking (TL32V20.DLL)
(a cracking approach to a "model" protection scheme)

by Xoanon/PNC

Courtesy of Fravia's page of reverse engineering
As you'll read, this was intended as a message to +ORC, since anon.penet has unfortunately closed, Xoanon sent it to me. I'll simply publish it here (I think it's worth) and hope that +ORC will see it (and may be he'll also start thinking about REOPENING a bilateral channel asap :-)
About this essay: the interest of it lays (IMHO) in the following three elements 1)It's a "model" protection scheme, i.e. a scheme that protectionists "buy" and use "ready-made", which is interesting; 2) there is a "double checking", as Xoanon explains, the protection checks TWICE if you entered the correct unlock sequence; 3) Xoanon style is "refreshing", he cracks with enthusiasm and good will

Hi +ORC! I'm an italian cracker, my name is Xoanon and i crack for PiNNACLE
(an utility group). D'ya know them? I hope you do!
First, sorry for my english... i don't think it's too bad, yet maybe
sometimes i don't explain myself very well! :)
In advance, i want to thank you for all your work! I think every
(or nearly every) new cracker in the world has learned this art from your
tutorial (me, i'm one of them!) .... So, back to the reason of this email:
you said "if u discover something new about protections, tell me.... i
will admit you to my +HCU and you will receive the missing lessons" ...
Well, i think i've something for you! Surely u'd know this already, or
maybe some of your +HCU students discovered it already.... but i'll try! :)
Well, my work is about a DLL used to protect W95 programs, the TL32V20.DLL.
I think the real name of this DLL is TimeLOCK, but who cares? i found a lot
of programs protected with it, like NetFusion Object 2.0, E-BroadCaster 1.0,
GeoBoy 1.3.1 .... and there are many others out there! I hope ya'll like it.

-----------------------------------------------------------------------------
TimeLOCK DLL
"a cracking approach", by Xoanon/PNC
-----------------------------------------------------------------------------

The DLL i will talk about is a DLL frequently used to protect commercial
programs distributed on the web. This DLL provide a time limit protection:
after xx days your program will not run anymore without purchasing.
The protection scheme is quite simple:

1) You are given a serial number by the program itself
2) You are asked to enter an unlock code calculated from this #
3) Name,Company and other stuffs doesn't interest the protection

Here the intersting findings:
1) Everytime the program is installed the serial provided changes.
2) The registering information are stored in the W95 Registry AND
in a file .TSF stored in some locations of your HD, in encrypted form.

For example, in GeoBoy v1.3.1 (one of the many programs protected with TimeLOCK)
if you search the registry for the word "GeoBoy" you will find some locations
where there are a bunch of strange characters.... that's your information,
encrypted.

But in this approach we will crack the DLL brutally, so we will not care
much about the registry!
Finally, if you want to reinstall it after the trial is expired (eh eh....
are you too lazy to try cracking it??? :) you have to COMPLETELY clean up
the registry (all branches where the word "Geoboy" dwells).

Now some Frequently Asked Questions:

Q:So, WHICH programs use this DLL? Where can I find them?

A:Well, i found a lot of programs that do use this DLL .... for example:
E-BroadCaster, NetObject Fusion v2.0, GeoBoy v1.3.1. They're all on the web,
search them using AltaVista or some other engine. Simply put in the name
of the program you are looking for, and then get it!

Q:Ok dude, i found that program! how can i see if it's protected with
the DLL ?

A:Obvious..... it has to load it from your HD everytime it runs... so, simply
search it with a DIR /S (will dwell most of the time inside the installation
directory of your new program, or else inside WIN/SYSTEM)

Ok boyz, now let's go cracking!
In this approach i will use as example target the program GeoBoy v1.3.1.
Find it on the web, it's done by NDG Software so i think you'll easily find
it (every software house has at least an homepage!).
Well, fire your SoftICE as usually, light your cigarette (like me, or if
you prefer the +ORC way, prepare a good Martini Vodka!) and install GeoBoy.
Installed? Ok, now run it! You will see the classic TimeLOCK window (it's
the same in all the programs protected with it, this makes it easy to see
if a program use this protection scheme). Enter a name, a company and an
unlock code. As you can see, you have in the window 3 edit lines.
Now enter in SoftICE and act as usual with password-protected programs:

.TASK

hmmmm is GeoBoy its task name? ...... found! Let's do an HWND on it!

.HWND GEOBOY

good! let's see... we're searching for some edit boxes.... found!

Handle hQueue SZ QOwner Class Name Window Procedure
....... .... .. ...... .... .............
052C(2) 0D57 32 GEOBOY Edit 177F:00000BF4 *
0508(2) 0D57 32 GEOBOY Edit 177F:00000BF4 *
050C(2) 0D57 32 GEOBOY Static 178f:000052FA
0510(2) 0D57 32 GEOBOY Edit 177f:00000BF4 *
....... .... .. ...... .... .............

We found 3 edit references.... let's try BMSGging the first (but will work
alsoBMSGging on the others)

. BMSG 052C WM_GETTEXT

Break due to BMSG 052C WM_GETTEXT !!! SoftICE pops up again!!!
Well, now you are inside Windos95 Kernel (if i remember well) ...
First, disable the breakpoint with BD 00 (or it will break on anyother
GETWINDOWTEXT function.... generally if you found an entry point you
should disable the BP after...).
Now step some instructions (not too many) until you reach TL32V20.
We have reached the DLL, now you have to show all your cracking capabilities!
Well.... step step step and step, watching the EAX,ECX,EDI,ESI after every
CALL or MOV EAX or MOV ECX or LEA EAX or LEA ECX (with D ).
You'll soon find that the DLL use these register to store the addresses to
everything you enter (name,company,unlock code) and also for the serial
number (generated at every install) and the correct unlock code.
You will also notice that the unlock code (es. 121212) you entered is stored
at EBP-14, while the correct one is stored at EBP-28.
Can we crack our target faking the MOV and LEA to these register? YES!
Watch this piece of code (you will reach it after some stepping once you
are working inside the DLL):
......
LEA EAX, [EBP-28]
PUSH EAX
CALL 10001D08 < Generate the correct unlock code "for.class" tppabs="http://fravia.org/for.class" the serial number
you're provided with
ADD ESP,04
LEA EAX,[EBP-14] < do "D [EBP-14]" and you'll see the code you entered
LEA ECX,[EBP-28] < do "D [EBP-28]" and you'll see the CORRECT code
PUSH EAX < save the location
PUSH ECX < save the location
......

Well..... we found something interesting, don't you think? Try immediately
to change the LEA EAX,[EBP-14] in LEA EAX,[EBP-28]. In this way, the correct
code is moved in EAX instead of the bogus code that we have entered.
Act as usual (write down some bytes after and some before these LEA,
write down also the bytes of the changed instructions, search them with
your hex-editor inside TL32V20.DLL and patch it). To make your life easy,
write down and use as search string a LOT of bytes before the LEA instruction,
or you will find a lot of occurences of the same sequence inside the file.
Ok, patched? Well, now try it and look if it works! Load back GeoBoy and
enter whatever you want as unlock code. Wow! it seems to work! it says
"Thanks for purchasing!" Eh eh.... Xoanon rulez!! :) Now you think that your
program is completely registered. But...... But? Try to load it another
time...... AAARGH!!!! The time-limit reminder pops up again! Why?
Well, it seems there are some other instructions referring to the code you
entered... Ok! Fire SoftICE again and back to work! Reach again the point
where you found the LEA EAX,[EBP-14] (now changed in [EBP-28]). Step a
little ahead and...... eh eh... look at this (some instructions after):

..........
ADD ESP,08
TEST EAX,EAX < checks if the values at [EAX] and [ECX] are the same....
now they are, 'coz we patched the DLL before.

JNZ 10004028 < if EAX isn't 0 (bad unlock code) will jump. Now no, 'coz
EAX is 0.

LEA EAX,[EBP-14] < Eh eh.... this is the instruction we are searching for!
As you see with "D EAX", it will move again in EAX the
code you entered (which is a bad code, obviously)....
Probably we need to change it too? YEAH!!!

PUSH EAX < Saves the location
..........

This is the end. Act as you did before, changing this occurrence of
LEA EAX,[EBP-14] in a LEA EAX,[EBP-28], in order to move again inside
EAX the correct code), then search and replace these bytes in
TL32V20.DLL.
Try again to run the program..... it WORKS!!!!!!!!
To be really sure, do the following:
1) Save your patched *.dll
2) clean from the registry all the entries which refer to GeoBoy
3) delete the file .TSF inside the GeoBoy directory and
4) reinstall the whole program anew
Now simply copy your patched DLL over the original one and run GeoBoy.
Enter whatever you want, it says "Ok,registered"... Exit, run again and
again and again for ever... you won't see anymore the timelimit screen!

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Done by Xoanon/PiNNACLE in May 1997

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The TimeLOCK_DLL cracking (TL32V20.DLL) (a cracking approach to a "model" protection scheme)

by Xoanon/PNC

The TimeLOCK_DLL cracking (TL32V20.DLL)
(a cracking approach to a "model" protection scheme)