marigold.htm

DoNotWasteTime_MrCracker@@YGHPBDPBEIPAEPAI@Z
(Timelock vagaries inside Ulead Gif Animator 2.0 - tl303inj.dll)

by Marigold

(16 January 1998)

Timelock

Courtesy of fravia's page of reverse engineering

Well, Marigold sent a very interesting letter, the first part is reported here, and regards Timelock 3, the second part has been annexed to UncleVan's recent essay about Mijenix's targets. You'll find the relevant link at the bottom.
Enjoy!

14 January 1998
Dear Fravia+,

It is not an essay. Just some words in discussion.
I like your site very much and think that the level of expertise 
one meets here may satisfy the most demanding. Moreover, high 
cultural standards of essays (slightly edited by ...) are 
unparalleled among similar sites. I do not belong to any group 
and visiting such places gives me encouragement necessary to 
overcome my laziness. 
But enough appraisals, hereafter I will follow "Criticize" 
section of your rules. I think the young and innocent who you 
teach should better know many different solutions to a problem 
than the only one given even if somebody considers it the best. 

I first found your site when I was looking for some information 
on TimeLock. I had just visited the Preview Software site and 
seen all that boasting about TimeLock version 3.xx. Needless to 
say, I was happy to find out that an organized effort is under 
way to defeat this monster. To my disappointment it was only 
about version 2-. And all the 9 essays on the topic gave really 
only ONE solution. Of cause, the solution with the unlocking key 
is very elegant. I am not going to discuss other people's 
aesthetic ideals but in cracking (... comme a la guerre) 
pragmatism provides the steadiest basis. And as far as pragmatism 
is concerned, TimeLock protection in all targets I've seen so far 
was within the famous scheme:
...
call ProtectionFunction
cmp eax, RightValue
jnz SomeBadProcedure
...

tl32v20.dll contains several ...ProtectionFunctions... and comparison 
logic is slightly more sophisticated, but it actually makes no 
difference. In my deep conviction such protection schemes MUST be 
bypassed.  Why should I fuss about satisfying some perverted 
check, if in most cases it is enough to substitute call operator 
with 

mov eax, RightValue

or to do a similar thing and after that you may delete-and-forget 
all that tl32v20.dll, *.lic etc?  So far this approach was tested 
with HiProfiler for VC++ and VB by TracePoint Technologies, 
Diskeeper 3.0 (both server and workstation versions), 
PowerBuilder by Sybase, QuickView Plus 4.50 by Inso Corp. and 
worked well. (In qvp.dll they combined all calls to TimeLock 
functions inside an exported procedure named QVPTrialWareStart 
which must return non-zero. Very nice of them.)

~~~~~
Man is selling a powder against cockroaches.
- How it works?
- You must catch a cockroach, put some powder into its mouth and 
  make it to swallow.
- If I caught a cockroach, I could just smash it!
- This method is also possible.
~~~~~

TimeLock 3.xx is another matter. I studied only one target, Ulead 
Gif Animator 2.0 (I obtained it through TuCows, don't remember 
where); executable ga_main.exe protected with TimeLock version 
3.03 (tl303inj.dll). This DLL has two exported functions: 
DoNotWasteTime_MrCracker@@YGHPBDPBEIPAEPAI@Z and 
PleaseTraceIntoMe_MrCracker@@YGKKKPAEPAXKK@Z. (sic!)

Protection is based on "wrapping" technique, as they call it. For 
the sake of brevity and considering your expertise, I'll omit 
trivial details and describe only highlights. Protection encrypts 
a short block of code after the program entry point making 
impossible to find it in the listing; creates an additional 
section in .exe file, named PREVIEW; and places program entry 
point there. Code at this new entry point looks like that:

...
call tl303inj.PleaseTraceIntoMe_MrCracker
call [eax]

If protection check fails, the function returns address of 
ExitProcess. If check is OK, the function decrypts program code 
(Read- and then WriteProcessMemory) and returns address of the 
original entry point. How did I find it? Just took an advice 
given in the name of the function. If you traced into it after 
the call of WriteProcessMemory, you know the entry point (6AB60), 
length of encrypted code (362 bytes) and the code itself. The 
final solution is obvious after that. (In my case the only 
complication was that the trial period has expired before I 
started reverse engineering and nasty thing didn't start 
application at its own will.)  All this does not look 
particularly tough, but TimeLock 3.xx protection may still not, 
of course, be considered as defeated. A new glorious goal for the 
TimeLock project participants! I guess in the nearest future 
there will be no lack of targets.

I confess now that the real reason to write this letter was the 
essay by Uncle Van on Mijenix's target...

     Many kisses,
      Marigold

mari-g(at)usa(point)net

see

uvessa_2.htm in order to read the rest of this very interesting Marigold's contribute!

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