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
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
|
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Code based from these two awesome projects:
- DPAPICK : https://bitbucket.org/jmichel/dpapick
- DPAPILAB : https://github.com/dfirfpi/dpapilab
"""
from . import crypto
from .credhist import CredHistFile
from .system import CredSystem
from .eater import DataStruct, Eater
from collections import defaultdict
import codecs
import hashlib
import struct
import os
class MasterKey(DataStruct):
"""
This class represents a MasterKey block contained in a MasterKeyFile
"""
def __init__(self, raw=None):
self.decrypted = False
self.key = None
self.key_hash = None
self.hmacSalt = None
self.hmac = None
self.hmacComputed = None
self.cipherAlgo = None
self.hashAlgo = None
self.rounds = None
self.iv = None
self.version = None
self.ciphertext = None
DataStruct.__init__(self, raw)
def parse(self, data):
self.version = data.eat("L")
self.iv = data.eat("16s")
self.rounds = data.eat("L")
self.hashAlgo = crypto.CryptoAlgo(data.eat("L"))
self.cipherAlgo = crypto.CryptoAlgo(data.eat("L"))
self.ciphertext = data.remain()
def decrypt_with_hash(self, sid, pwdhash):
"""
Decrypts the masterkey with the given user's hash and SID.
Simply computes the corresponding key then calls self.decrypt_with_key()
"""
self.decrypt_with_key(crypto.derivePwdHash(pwdhash=pwdhash, sid=sid))
def decrypt_with_password(self, sid, pwd):
"""
Decrypts the masterkey with the given user's password and SID.
Simply computes the corresponding key, then calls self.decrypt_with_hash()
"""
try:
pwd = pwd.encode("UTF-16LE")
except Exception:
return
for algo in ["sha1", "md4"]:
self.decrypt_with_hash(sid=sid, pwdhash=hashlib.new(algo, pwd).digest())
if self.decrypted:
break
def decrypt_with_key(self, pwdhash):
"""
Decrypts the masterkey with the given encryption key.
This function also extracts the HMAC part of the decrypted stuff and compare it with the computed one.
Note that, once successfully decrypted, the masterkey will not be decrypted anymore; this function will simply return.
"""
if self.decrypted or not pwdhash:
return
# Compute encryption key
cleartxt = crypto.dataDecrypt(self.cipherAlgo, self.hashAlgo, self.ciphertext, pwdhash, self.iv,
self.rounds)
self.key = cleartxt[-64:]
hmacSalt = cleartxt[:16]
hmac = cleartxt[16:16 + int(self.hashAlgo.digestLength)]
hmacComputed = crypto.DPAPIHmac(self.hashAlgo, pwdhash, hmacSalt, self.key)
self.decrypted = hmac == hmacComputed
if self.decrypted:
self.key_hash = hashlib.sha1(self.key).digest()
class CredHist(DataStruct):
"""This class represents a Credhist block contained in the MasterKeyFile"""
def __init__(self, raw=None):
self.version = None
self.guid = None
DataStruct.__init__(self, raw)
def parse(self, data):
self.version = data.eat("L")
self.guid = "%0x-%0x-%0x-%0x%0x-%0x%0x%0x%0x%0x%0x" % data.eat("L2H8B")
class DomainKey(DataStruct):
"""This class represents a DomainKey block contained in the MasterKeyFile.
Currently does nothing more than parsing. Work on Active Directory stuff is
still on progress.
"""
def __init__(self, raw=None):
self.version = None
self.secretLen = None
self.accesscheckLen = None
self.guidKey = None
self.encryptedSecret = None
self.accessCheck = None
DataStruct.__init__(self, raw)
def parse(self, data):
self.version = data.eat("L")
self.secretLen = data.eat("L")
self.accesscheckLen = data.eat("L")
self.guidKey = "%0x-%0x-%0x-%0x%0x-%0x%0x%0x%0x%0x%0x" % data.eat("L2H8B") # data.eat("16s")
self.encryptedSecret = data.eat("%us" % self.secretLen)
self.accessCheck = data.eat("%us" % self.accesscheckLen)
class MasterKeyFile(DataStruct):
"""
This class represents a masterkey file.
"""
def __init__(self, raw=None):
self.masterkey = None
self.backupkey = None
self.credhist = None
self.domainkey = None
self.decrypted = False
self.version = None
self.guid = None
self.policy = None
self.masterkeyLen = self.backupkeyLen = self.credhistLen = self.domainkeyLen = 0
DataStruct.__init__(self, raw)
def parse(self, data):
self.version = data.eat("L")
data.eat("2L")
self.guid = data.eat("72s").decode("UTF-16LE").encode("utf-8")
data.eat("2L")
self.policy = data.eat("L")
self.masterkeyLen = data.eat("Q")
self.backupkeyLen = data.eat("Q")
self.credhistLen = data.eat("Q")
self.domainkeyLen = data.eat("Q")
if self.masterkeyLen > 0:
self.masterkey = MasterKey()
self.masterkey.parse(data.eat_sub(self.masterkeyLen))
if self.backupkeyLen > 0:
self.backupkey = MasterKey()
self.backupkey.parse(data.eat_sub(self.backupkeyLen))
if self.credhistLen > 0:
self.credhist = CredHist()
self.credhist.parse(data.eat_sub(self.credhistLen))
if self.domainkeyLen > 0:
self.domainkey = DomainKey()
self.domainkey.parse(data.eat_sub(self.domainkeyLen))
def get_key(self):
"""
Returns the first decrypted block between Masterkey and BackupKey.
If none has been decrypted, returns the Masterkey block.
"""
if self.masterkey.decrypted:
return self.masterkey.key or self.masterkey.key_hash
elif self.backupkey.decrypted:
return self.backupkey.key
return self.masterkey.key
def jhash(self, sid=None, context='local'):
"""
Compute the hash used to be bruteforced.
From the masterkey field of the mk file => mk variable.
"""
if 'des3' in str(self.masterkey.cipherAlgo).lower() and 'hmac' in str(self.masterkey.hashAlgo).lower():
version = 1
hmac_algo = 'sha1'
cipher_algo = 'des3'
elif 'aes-256' in str(self.masterkey.cipherAlgo).lower() and 'sha512' in str(self.masterkey.hashAlgo).lower():
version = 2
hmac_algo = 'sha512'
cipher_algo = 'aes256'
else:
return 'Unsupported combination of cipher {cipher_algo} and hash algorithm {algo} found!'.format(
cipher_algo=self.masterkey.cipherAlgo, algo=self.masterkey.hashAlgo)
context_int = 0
if context == "domain":
context_int = 2
elif context == "local":
context_int = 1
return '$DPAPImk${version}*{context}*{sid}*{cipher_algo}*{hmac_algo}*{rounds}*{iv}*{size}*{ciphertext}'.format(
version=version,
context=context_int,
sid=sid,
cipher_algo=cipher_algo,
hmac_algo=hmac_algo,
rounds=self.masterkey.rounds,
iv=self.masterkey.iv.encode("hex"),
size=len(self.masterkey.ciphertext.encode("hex")),
ciphertext=self.masterkey.ciphertext.encode("hex")
)
class MasterKeyPool(object):
"""
This class is the pivot for using DPAPIck.
It manages all the DPAPI structures and contains all the decryption intelligence.
"""
def __init__(self):
self.keys = defaultdict(
lambda: {
'password': None, # contains cleartext password
'mkf': [], # contains the masterkey file object
}
)
self.mkfiles = []
self.credhists = {}
self.mk_dir = None
self.nb_mkf = 0
self.nb_mkf_decrypted = 0
self.preferred_guid = None
self.system = None
def add_master_key(self, mkey):
"""
Add a MasterKeyFile is the pool.
mkey is a string representing the content of the file to add.
"""
mkf = MasterKeyFile(mkey)
self.keys[mkf.guid]['mkf'].append(mkf)
# Store mkfile object
self.mkfiles.append(mkf) # TO DO000000 => use only self.keys variable
def load_directory(self, directory):
"""
Adds every masterkey contained in the given directory to the pool.
"""
if os.path.exists(directory):
self.mk_dir = directory
for k in os.listdir(directory):
try:
with open(os.path.join(directory, k), 'rb') as f:
self.add_master_key(f.read())
self.nb_mkf += 1
except Exception:
pass
return True
return False
def get_master_keys(self, guid):
"""
Returns an array of Masterkeys corresponding to the given GUID.
"""
return self.keys.get(guid, {}).get('mkf')
def get_password(self, guid):
"""
Returns the password found corresponding to the given GUID.
"""
return self.keys.get(guid, {}).get('password')
def add_credhist_file(self, sid, credfile):
"""
Adds a Credhist file to the pool.
"""
if os.path.exists(credfile):
try:
with open(credfile) as f:
self.credhists[sid] = CredHistFile(f.read())
except Exception:
pass
def get_preferred_guid(self):
"""
Extract from the Preferred file the associated GUID.
This guid represent the preferred masterkey used by the system.
This means that it has been encrypted using the current password not an older one.
"""
if self.preferred_guid:
return self.preferred_guid
if self.mk_dir:
preferred_file = os.path.join(self.mk_dir, u'Preferred')
if os.path.exists(preferred_file):
with open(preferred_file, 'rb') as pfile:
GUID1 = pfile.read(8)
GUID2 = pfile.read(8)
GUID = struct.unpack("<LHH", GUID1)
GUID2 = struct.unpack(">HLH", GUID2)
self.preferred_guid = "%s-%s-%s-%s-%s%s" % (
format(GUID[0], '08x'), format(GUID[1], '04x'), format(GUID[2], '04x'), format(GUID2[0], '04x'),
format(GUID2[1], '08x'), format(GUID2[2], '04x'))
return self.preferred_guid
return False
def get_cleartext_password(self, guid=None):
"""
Get cleartext password if already found of the associated guid.
If not guid specify, return the associated password of the preferred guid.
"""
if not guid:
guid = self.get_preferred_guid()
if guid:
return self.get_password(guid)
def get_dpapi_hash(self, sid, context='local'):
"""
Extract the DPAPI hash corresponding to the user's password to be able to bruteforce it using john or hashcat.
No admin privilege are required to extract it.
:param context: expect local or domain depending of the windows environment.
"""
self.get_preferred_guid()
for mkf in self.mkfiles:
if self.preferred_guid == mkf.guid:
return mkf.jhash(sid=sid, context=context)
def add_system_credential(self, blob):
"""
Adds DPAPI_SYSTEM token to the pool.
blob is a string representing the LSA secret token
"""
self.system = CredSystem(blob)
def try_credential(self, sid, password=None):
"""
This function tries to decrypt every masterkey contained in the pool that has not been successfully decrypted yet with the given password and SID.
Should be called as a generator (ex: for r in try_credential(sid, password))
"""
# All master key files have not been already decrypted
if self.nb_mkf_decrypted != self.nb_mkf:
for guid in self.keys:
for mkf in self.keys[guid].get('mkf', ''):
if not mkf.decrypted:
mk = mkf.masterkey
if mk:
mk.decrypt_with_password(sid, password)
if not mk.decrypted and self.credhists.get(sid) is not None:
# Try using credhist file
self.credhists[sid].decrypt_with_password(password)
for credhist in self.credhists[sid].entries_list:
mk.decrypt_with_hash(sid, credhist.pwdhash)
if credhist.ntlm is not None and not mk.decrypted:
mk.decrypt_with_hash(sid, credhist.ntlm)
if mk.decrypted:
yield u'masterkey {masterkey} decrypted using credhists key'.format(
masterkey=mk.guid.decode())
self.credhists[sid].valid = True
if mk.decrypted:
# Save the password found
self.keys[mkf.guid]['password'] = password
mkf.decrypted = True
self.nb_mkf_decrypted += 1
yield True, u'{password} ok for masterkey {masterkey}'.format(password=password,
masterkey=mkf.guid.decode())
else:
yield False, u'{password} not ok for masterkey {masterkey}'.format(password=password,
masterkey=mkf.guid.decode())
def try_credential_hash(self, sid, pwdhash=None):
"""
This function tries to decrypt every masterkey contained in the pool that has not been successfully decrypted yet with the given password and SID.
Should be called as a generator (ex: for r in try_credential_hash(sid, pwdhash))
"""
# All master key files have not been already decrypted
if self.nb_mkf_decrypted != self.nb_mkf:
for guid in self.keys:
for mkf in self.keys[guid].get('mkf', ''):
if not mkf.decrypted:
mk = mkf.masterkey
mk.decrypt_with_hash(sid, pwdhash)
if not mk.decrypted and self.credhists.get(sid) is not None:
# Try using credhist file
self.credhists[sid].decrypt_with_hash(pwdhash)
for credhist in self.credhists[sid].entries_list:
mk.decrypt_with_hash(sid, credhist.pwdhash)
if credhist.ntlm is not None and not mk.decrypted:
mk.decrypt_with_hash(sid, credhist.ntlm)
if mk.decrypted:
yield True, u'masterkey {masterkey} decrypted using credhists key'.format(
masterkey=mk.guid)
self.credhists[sid].valid = True
break
if mk.decrypted:
mkf.decrypted = True
self.nb_mkf_decrypted += 1
yield True, u'{hash} ok for masterkey {masterkey}'.format(hash=codecs.encode(pwdhash, 'hex').decode(),
masterkey=mkf.guid.decode())
else:
yield False, u'{hash} not ok for masterkey {masterkey}'.format(
hash=codecs.encode(pwdhash, 'hex').decode(), masterkey=mkf.guid.decode())
def try_system_credential(self):
"""
Decrypt masterkey files from the system user using DPAPI_SYSTEM creds as key
Should be called as a generator (ex: for r in try_system_credential())
"""
for guid in self.keys:
for mkf in self.keys[guid].get('mkf', ''):
if not mkf.decrypted:
mk = mkf.masterkey
mk.decrypt_with_key(self.system.user)
if not mk.decrypted:
mk.decrypt_with_key(self.system.machine)
if mk.decrypted:
mkf.decrypted = True
self.nb_mkf_decrypted += 1
yield True, u'System masterkey decrypted for {masterkey}'.format(masterkey=mkf.guid.decode())
else:
yield False, u'System masterkey not decrypted for masterkey {masterkey}'.format(
masterkey=mkf.guid.decode())
|