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[Crackme/KeygenMe] Crackme for HackForums.


mrexodia

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Hello everyone,

Some time ago I posted an easy (1hour coding) crackme on hackforums.net but maybe here it'll be solved here faster smile.png

This is a small crackme with some anti analysis, should be

easy!

Rules:

* No patching

* Valid solution is tutorial+used sources

* Get password!

Mr. eXoDia // T.P.o.D.T 2012

mr.exodia.tpodt@gmail.com

http://www.tpodt.com

Max time to solve should be 10 minutes (solve, not investigate)...

Best regards,

Mr. eXoDia

CrackMe_HackForums-TPoDT.rar

https://mega.nz/#!n4xmkArQ!ee5ElrB54EDNFMS5K2lvNk4q3O4AKSU2_eVpSjmUFlA

Edited by Mr. eXoDia
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Actually, i don't know how your loop work, a long loop :-? dots.gif After that we have an array.

ex: inputserial = 1234 ----Loop---> 4F634667 E59B358C 281D496E E9FBA3F4 8FFDA27F.

And now we work on 5 "Numbers" above by XOR-ing Algo, the final result must be equal = $Part1

What i want to say here is we have final result, that mean the loop can be reversed to compute serial.

But your loop so complicated, i have no ideal to solve it elvis.gif

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Yeah, scanned but i think sha0-1 with modified can not be reversed so i post my wonder.

I'm not hopefully to solve any target anymore smile.png just do for fun coz i don't have time to improve my skill smile.png And yes, your kgm now beyond my level, good keygenme to me smile.png Gonna save it within tutorial to learn smile.png

Edit abit for more clear smile.png

Edited by kakamail
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Mr eXoDia, Hackforums is no good for anything related to reverse engineering, Unless your looking for script kiddies want to be coders you should stay away from there before the 1337 h4cKers ddos you with there ub4r vb6 ddos t00lz. Sorry for going off topic I just know how that forum is... Anyway I will attept your keygenme tonight and hopefully have some luck :)

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Mr eXoDia, Hackforums is no good for anything related to reverse engineering, Unless your looking for script kiddies want to be coders you should stay away from there before the 1337 h4cKers ddos you with there ub4r vb6 ddos t00lz. Sorry for going off topic I just know how that forum is... Anyway I will attept your keygenme tonight and hopefully have some luck smile.png

Hmm, I agree but someone there provided me an Armadillo v8.60 Custom Build! I needed 10 posts to use the PM system ;)

Anyway, I think you can solve this. Don't hesitate to brute-force... A good coded bruter can do this in 4-5 minutes (on a quad core pc)

Greetings

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open it with olly debug 2 and enter that serial smile.png considering its a Multi Serial "crackme" try the serials "codebugs" and "backtothedrawingboard" all wich work under ollydebug 2 without patching anything. Also see below for requested tutorial as part of the crackme....

Tutorial:

1. Open the challenge with OllyDebug2

2. press run

3. enter any serial and press check

4. Olly will break 2 or 3 times on the INT3

5. press F9 to continue execution

5. good boy message.

Challanged solved as requested with tutorial and no patching, while a good coder could code a "brute forcer" a smart coder doesn't even need to code to solve this in 20 seconds...

Thanks and Regards....

Edited by Departure
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Haha, indeed a really smart solution. But the algo is designed to go to the badboy place when an INT3 occurs...

Anyways, really smart...

Greetings

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Serial : 135FF6D5042EDCB42

Source code with some explication attached. To compile you'll need freepascal and lazarus (or CodeTyphon)

Probably not the fastest or easiest way to find a serial but anyway.. i got the "goodboy" popup at last biggrin.png

BTW.. I liked your INT3 and OutputDebugStringA trick wink.png

Tutorial is also added in this post

Update : Fixed typo's in PDF

crackme_sol.rar

CrackMe.pdf

Edited by DE!
  • Like 4
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@DE!: Thanks a lot for your solution, I'll post it on my website smile.png

Greetings,

Mr. eXoDia

Thanks :) Btw.. i fixed some typo mistakes in the pdf so i'll upload an updated one later this evening

  • Like 1
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Thanks DE! for the tutorial, May I suggest using threads in your code to make brute forcing faster you could have 2 or 4 threads, 1 thread starting from 10000000, 1 thread starting from FFFFFFFF and going backwards, then if you wanted more than 2 threads start the other 2 at 80000000 one increasing while the other decreases

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  • 2 weeks later...

Thanks DE! for the tutorial, May I suggest using threads in your code to make brute forcing faster you could have 2 or 4 threads, 1 thread starting from 10000000, 1 thread starting from FFFFFFFF and going backwards, then if you wanted more than 2 threads start the other 2 at 80000000 one increasing while the other decreases

Thanks for the suggestion!.. I modified the code so it would run in 4 threads

$10000000 -> $50000000

$50000001 -> $A0000000

$A0000001 -> $E0000000

$E0000001 -> $FFFFFFFF

and its indeed faster, although i had to add some sleep(1) inside the threads, otherwise cpu would freak out...The sleep(1) on the other hand made it slower... Thanks!

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I had to add some sleep(1) inside the threads, otherwise cpu would freak out...

Just make the thread priority of 1 thread very low or just use 3 threads...

Greetings

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SetThreadPriority(GetCurrentThread , THREAD_PRIORITY_LOWEST);

you can use THREAD_PRIORITY_HIGHEST, THREAD_PRIORITY_ABOVE_NORMAL, THREAD_PRIORITY_NORMAL, THREAD_PRIORITY_BELOW_NORMAL, THREAD_PRIORITY_LOWEST and THREAD_PRIORITY_IDLE

Edited by Departure
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