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Passz CheckS
Passz CheckS
Challenge Description
You are given a password checker program which is encrypted through an algorithm, decipher,decomipiler and decode the file to find the password
Inspect binary file and Locate custom alphabet and encoded flag strings password_checker | grep -E "(Correct!|Wrong!|Usage:|[A-Za-z0-9+/]{10,})"
Locate XOR key (12 bytes) xxd password_checker | grep -A2 -B2 "0a0b 0c0d
Locate expected-hash bytes (0x7a repeated) grep -a -b -o "zzzz" password_checker xxd password_checker | sed -n '94,96p'
Compute password from key and target byte 0x7a
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python3 - <<'PY' xor_key = [0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14,
0x15] expected = 0x7A password = ''.join(chr(expected ^ b) for b in xor_key) print(password) PY
Retrieve flag ./password_checker "pqvwtujkhino"
Final flag is:
CBCV{CiCaDAzznotz141}
Flag
CBCV{CiCaDAzznotz141}