sibesa's sibesa's crackme 1
| Download sibesa__s_crackme_1.zip, 3 kb (password: crackmes.de) Browse contents of sibesa__s_crackme_1.zip 4 steps good luck"
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Solutions
Solution by phueghy, published 19. jun, 2005; download (41 kb), password: crackmes.de or browse.
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Discussion and comments
| haggar 18. Jun 2005 | Does this crackme has a bug? I solved it , sometimes serial for level4 works and sometimes not. Reason is here 00401449 MOV EDI,DWORD PTR SS:[EBP+14] value [EBP+14] is used for XORing later, but this value is not constant and I don't know on what logic it changes. One time it's 10B6A50D and second time is D4FEE33B. |
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| GR33d 19. Jun 2005 | oh yes.... in my case it was 9448834Ah .... strange lol i couldnt find out the logic too : MOV EDI,DWORD PTR SS:[EBP+14] .... but it worked |
| CuTedEvil 19. Jun 2005 | I'm checking level 4.. <esi doesn't inceremnt in the loop, and all solutions seems to be wrong for this level!, you all failed to get the correct magic value, so i'll check it> |
| CuTedEvil 19. Jun 2005 | Crackme is OK! You just don't know where this value (which is sometimes is constant, n sometimes is not :P) comes from.. Just pay more attention, ur overlooking sth.. CuTedEvil |
| ap0x 19. Jun 2005 | It works ok, i solved it... Very nice crackme for newbies... Good work! |
| SunSatION 19. Jun 2005 | Yes, it works perfectly here! |
| m@rio_crk 19. Jun 2005 | this crkme is very good for newbies, haggar,GR33d: this [ebp+14] comes from stack, check the parameters of the actually call.. |
| haggar 19. Jun 2005 | Yep, I found it. I didn't pay attention first time since name/serial check are reall easy so didn't expected a trick. Ha ha, got me. |
| noops 20. Jun 2005 | hmmmmmm nice work.IM suprised |
| bgrimm 15. Jul 2005 | Just a technical note on the Solution posted by phuegy: Stated in solution: We loop through our name again, XORing every char with that magic value, SHLing the result by 2 and summing these values up at memory location EBP-8. ------------------ Actually the code only operates on the first character of the entered username. which is XOR'd and summed a number of times equal to the length of username. 0FB606 /MOVZX EAX,BYTE PTR DS:[ESI] ^^^^^^^ esi is never incremented in the loop, so the first character is always used. therefore, any username with the same first character and the same length will generate the same serial. nitpicking but that's just me. Regards, -bg |
| phueghy 24. Jul 2005 | bgrimm, thanks for pointing that out. Actually in my keygen I did what you said, but the solution states otherwise. I shall update that and maybe improve the code a little when I find some time. |
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