cryptcat's CrackmeD
| Download CrackmeD.zip, 136 kb (password: crackmes.de) Browse contents of CrackmeD.zip CrackmeD : Cryptcat
Difficulty: 2 - Needs a little brain (or luck) | RatingWaiting for at least 3 votes View profile of cryptcat » |
Solutions
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Discussion and comments
| cryptcat Author 27. May 2007 | How goes the reversing? |
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| Zaphod 31. May 2007 | Well, I have fished the serial for my name, but I don't know how it is generated... |
| Sturgeon 03. Jun 2007 | [b]Zaphod[/b] How did you made it? |
| Zaphod 03. Jun 2007 | Sturgeon: What puzzled me at first was how the program reads the entered name and serial. Once I found out about that and thereby found out where to break it was easy to fish the serial. I don't think I spoil anything by saying that the proggy uses WM_GETTEXT... cryptcat: I think there is a problem with the namelength. The name cannot be longer than 7 chars unless there is a separate algo for longer names ( which I can't find ). Is this intentional? |
| cryptcat Author 04. Jun 2007 | I have a mistake in my code. I messed up how the name length is checked. I'll update the program. |
| hound 09. Jun 2007 | Hmm, im really having trouble with this. There is soooo much random stuff in the crackme, and it won't break on anything. Any suggestions? |
| Zaphod 09. Jun 2007 | cryptcat: I have made a keygen, but it only works if the name is four chars long. Is this intentional? hound: Try setting a conditional breakpoint on CallWindowProc, condition MSG == WM_GETTEXT |
| hound 09. Jun 2007 | Sweet as, thanks for the help. Ive written a keygen too, its easy once I had the breakpoint ;). Thanks. The namelength is restricted to four characters only though.... 00403A88 . FF91 A0000000 CALL DWORD PTR DS:[ECX+A0] ;Converts name from unicode to ascii 00403A8E . 894424 10 MOV DWORD PTR SS:[ESP+10],EAX ;Store namelength 00403A92 . 895424 14 MOV DWORD PTR SS:[ESP+14],EDX 00403A96 . 837C24 10 04 CMP DWORD PTR SS:[ESP+10],4 00403A9B . 0F85 5F010000 JNZ CrackmeD.00403C00 ;If namelength != 4, jump (bad) Anyway, reasonably fun crackme. I suppose the hard thing about it is just all the random stuff, and finding where to break in the code (which I had help with....) |
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