def decrypt_and_check_url(ciphertext):
plaintext = decrypt_aes_cbc(ciphertext, oracle_key, iv)
plaintext = unpad_pkcs7(plaintext)
for c in plaintext:
if chr(c) not in string.printable:
raise Exception(plaintext)
return True
def attack_message(message):
blocks = chunks_of_bytearray(message, BLOCK_SIZE)
plaintext = []
for ix, _ in enumerate(blocks):
plaintext_block = attack_block(blocks, ix)
plaintext.extend(plaintext_block)
return unpad_pkcs7(bytearray(plaintext))
def main():
s1 = string_to_bytearray("ICE ICE BABY\x04\x04\x04\x04")
s2 = string_to_bytearray("ICE ICE BABY\x05\x05\x05\x05")
s3 = string_to_bytearray("ICE ICE BABY\x01\x02\x03\x04")
assert valid_pkcs7_padding(s1) == True
assert valid_pkcs7_padding(s2) == False
assert valid_pkcs7_padding(s3) == False
unpad_pkcs7(s1)
try:
unpad_pkcs7(s2)
raise Exception("challenge 2.15 failed.")
except ValueError as e:
pass
try:
unpad_pkcs7(s3)
raise Exception("challenge 2.15 failed.")
except ValueError as e:
pass
print("challenge 2.15 completed.")
def decrypt_and_check_admin(ciphertext):
plaintext = decrypt_aes_cbc(ciphertext, oracle_key, iv)
plaintext = unpad_pkcs7(plaintext)
return b';admin=true;' in plaintext
def decrypt_encoded_profile(encoded_profile):
plaintext = decrypt_aes_128_ecb(encoded_profile, oracle_key)
profile = unpad_pkcs7(plaintext)
return parse_url_params(profile.decode())