crackmes.one

sw33tLie's Input Magic

Author:
sw33tLie

Language:
C/C++

Upload:
3:21 PM 03/28/2019

Level:
1

Platform
Windows

Description

NO PATCHING ALLOWED! Find the right string (of any size) to input in the console in order to get the valid license message.

GautamGreat on 12:33 PM 03/29/2019: I dunno why but it crash in Windows 7 x86

Rufis_ on 6:51 PM 03/29/2019: Very easy?

omniarepair on 2:50 PM 03/30/2019: same here cant seem to get it work on windows 8 neither

kalipo on 9:53 AM 03/31/2019: The correct key is '?'

kalipo on 9:56 AM 03/31/2019: Actually the code just checks if the first character is ? the rest are ignored. So the answer is ? followed by anything

Moltivie on 8:16 AM 05/17/2019: When Ghidra comes in... http[s]://im[gu]r.c[o]m/a/6hM8a9K

evilprogrammer on 5:27 AM 07/16/2019: the answer is in this line: DIV ECX the line above means like this EDX

Parad0x13 on 3:28 AM 09/05/2019: License: ? "Congrats! This license is valid!" string easily found and xrefd only at 0xbf26c8 Analyzing the decomp for this function I see that: len(license) % 0x3c must equal 3 license must be larger than 0x2a license must be smaller than 0x48 This can be easily found with the following python: for n in range(0x2a + 1, 0x48): if n % 0x3c == 3: print(chr(n))

juansacco on 8:53 PM 10/04/2019: The crackme only checks for the serial to start with ? Does not check for size, smaller or larger than, so some of the explainations here are wrong. xor edx, edx ; Logical Exclusive OR mov ecx, 3Ch ; '

juansacco on 8:53 PM 10/04/2019: ENTER LICENSE: ? Congrats! This license is valid!