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dos cracking

Posted: Sat Mar 30, 2019 7:54 pm
by urbi_zg
Hello :)

Does anyone here in this forum have extensive experience and knowledge in the field of cracking DOS programs and could cracked an old DOS game (3x doc-check) ?

Re: dos cracking

Posted: Sat Mar 30, 2019 8:18 pm
by CodeExplorer
I've tried myself to do it but I've failed. But I am not a DOS cracker: still at entry level with DOS.
More info you send my by PM:
"Silmarils games, Ishar included, are interpreted, with the executable basically being a virtual machine implementation and not much else. Protection (as well as pretty much everything else) is also done in the interpreted bytecode so cracking it is a bit more difficult and time consuming than simply finding the right assembly instruction in the code and applying a JMP patch. You have to find the bytecode implementation of the protection scheme (i.e. figure out which file contains the protection routine and find the exact location of the routine in the file), learn how it works by learning what each interpreted command does and figure out a way to patch it by using interpreter's commands available to the game. After that you can either write a loader to do the patching in memory or patch the file directly (in this case you'll have to unpack it first since it's packed with a custom packer). I'm speaking from experience here as someone who cracked the game."

Loader + game (same protection)
https://www101.zippyshare.com/v/ThBxbZJC/file.html