hacktooth's KeygenMe again (LINUX)

Author:
hacktooth

Language:
C/C++

Upload:
2025-08-26 22:58

Download

Platform:
Unix/linux etc.

Difficulty:
2.5

Quality:
5.0

Arch:
x86-64

Downloads:
39

Writeups:
0

Comments:
4

Description

This executable is only for linux, i tested on Debian 12 Same KeygenMe same rules. Create a keygen! enJoy the music! (again)

Comments (4)
Writeups (0)

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MateiM on 2025-09-24 16:40: The key comparison is here: void __fastcall KeygenMeForm::OnLogin The user and password are visible at runtime. Use a debugger like gdb or IDA.

pale_delirium on 2025-11-08 05:48: Lots of fun. Thanks a lot. There was lots of cruft in the code. I never realized how messy C++ / GUI code is. I couldn't be bothered writing a full write up but here's my solution so BEWARE SPOILERS BELOW! *** SPOILER *** First upx unpack the executable. Then see this keygen python script for the solution. ``` import struct import sys def generate_key(username): # --- # Step 0: xor each lot of 4 characters with each other so we end up with a username 4 bytes long for the key generation. # We pad with null bytes if the chunks are shorter than 4 chars. # --- chunk_size = 4 starting_chunk = username.ljust(chunk_size, '\0').encode('ascii')[:4] starting_chunk_int = struct.unpack(' 4: for i in range(4, len(username), chunk_size): chunk = username[i:i + chunk_size].ljust(4, '\0').encode('ascii')[:4] chunk_int = struct.unpack('") print("\nExample: python {sys.argv[0]} asdf") else: username_input = sys.argv[1] key = generate_key(username_input) if key: print(f"Username: {username_input}") print(f"Key: {key}") ``` *** SPOILER ***

pale_delirium on 2025-11-08 05:49: Oops something got messed up in my last post. Trying one more time. Sorry, I'm new here. *** SPOILER BELOW *** ``` import struct import sys def generate_key(username): # --- # Step 0: xor each lot of 4 characters with each other so we end up with a username 4 bytes long for the key generation. # We pad with null bytes if the chunks are shorter than 4 chars. # --- chunk_size = 4 starting_chunk = username.ljust(chunk_size, '\0').encode('ascii')[:4] starting_chunk_int = struct.unpack(' 4: for i in range(4, len(username), chunk_size): chunk = username[i:i + chunk_size].ljust(4, '\0').encode('ascii')[:4] chunk_int = struct.unpack('") print("\nExample: python {sys.argv[0]} asdf") else: username_input = sys.argv[1] key = generate_key(username_input) if key: print(f"Username: {username_input}") print(f"Key: {key}") ```

yzx001 on 2025-11-15 16:42: def compute_key(username: str) - None: buffer = [0, 0, 0, 0] for i, c in enumerate(username): buffer[i % 4] ^= ord(c) uint_val = (buffer[3] (i * 8)) & 0xFF for i in range(4) ] key = ''.join(f"{b:02X}" for b in bytes_val) print(f'Enter you username: {username} and registration key: KGM-{key} in the application!')

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hacktooth's KeygenMe again (LINUX)