-
Notifications
You must be signed in to change notification settings - Fork 2
/
filescan.py
1384 lines (1298 loc) · 65.5 KB
/
filescan.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
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
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
#!/usr/bin/env python
# FileScan, version 1.2.2
# Copyright (C) 2012, Giovanni Pessiva <giovanni.pessiva at gmail.com>
# All rights reserved.
#
# This software is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# It is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this software. If not, see <http://www.gnu.org/licenses/>.
import sys
import os
import shutil
import magic
import StringIO
import re
import hashlib
import subprocess
import shlex
import zipfile
import cStringIO
from time import time
from androguard.core import androconf
from androguard.core.bytecodes.apk import ARSCParser
INFECTED_DEX_RISK = 0
INFECTED_ELF_RISK = 1
HIDDEN_APK_RISK = 2
HIDDEN_ELF_RISK = 3
HIDDEN_TXT_RISK = 4
EMBEDDED_APK = 5
SHELL_RISK = 6
SHELL_INSTALL_RISK = 7
SHELL_PRIVILEGE_RISK = 8
SHELL_OTHER_RISK = 9
LOW_RISK = "low"
HIGH_RISK = "high"
NULL_MALWARE_RISK = "null"
AVERAGE_MALWARE_RISK = "average"
HIGH_MALWARE_RISK = "high"
UNACCEPTABLE_MALWARE_RISK = "unacceptable"
class FileScan :
"""
Analyze the files inside an archive, listing interesting files such as:
- textual files
- android binary xml
- dex code
- apk, zip, jar, gzip, tar
- other compressed archives
- compiled executable or resources
"""
def __init__(self, file, raw=False, type="zip", apk_export_path="",
ENABLE_NET_CONNECTION = True,
DEBUG_IGNORE_CMD = False,
DEBUG_IGNORE_URL = False,
DEBUG_IGNORE_SMS = False) :
"""
@param file : specify the path of the file, or raw data
@param raw : specify (boolean) if "file" is a path or raw data
@param type : specify the archive type: "zip", "gzip", "tar", "rar"
@param apk_export_path: specify a path where to export the embedded apk files
found inside this package (e.g.: "/home/giova/samples/")
@param ENABLE_NET_CONNECTION : flag for disabling the connection
to the online malware lookup service
@param DEBUG_IGNORE_CMD : flag for disabling the search for shell commands
@param DEBUG_IGNORE_URL : flag for disabling the search for URL addresses
@param DEBUG_IGNORE_SMS : flag for disabling the search for phone numbers
"""
if file is None :
raise Exception("Missing parameter: file.")
if raw==False and not os.path.exists(file) :
raise Exception("The apk file can not be found: " + file)
# Parameters
self.apk_export_path = apk_export_path # Path where to save embedded apk (if any will be found)
self.enable_net_connection = ENABLE_NET_CONNECTION # Dont connect to Malware Hash Registry
self.ignore_cmd = DEBUG_IGNORE_CMD # Dont search for shell commands
self.ignore_url = DEBUG_IGNORE_URL # Dont search for URL addresses
self.ignore_sms = DEBUG_IGNORE_SMS # Dont search for phone numbers
# Dictionaries of <file name> : <data>
self.files = {} # store raw data of interesting files
self.files_types_descr = {} # store file type description
self.files_types_mime = {} # store file mime type
self.files_compressed_filescan = {} # store FileScan objects
# Dictionary of <file type> : <count of total files>
self.types = {}
# Strings associated to file types
self.TYPE_MULTIMEDIA = "multimedia"
self.TYPE_BINARY_XML = "android xml"
self.TYPE_PACKAGE = "android apk"
self.TYPE_ARCHIVE = "compressed archive"
self.TYPE_XML = "xml"
self.TYPE_TEXT = "text"
self.TYPE_DEX = "dex"
self.TYPE_ELF = "elf"
self.TYPE_ARSC = "android resource"
self.TYPE_BINARY = "unknown binary"
self.TYPE_OTHER = "other"
self.TYPE_EMPTY = "empty file"
# Lists of <file name>
self.filelist_text = []
self.filelist_xml = []
self.filelist_dex = []
self.filelist_elf = []
self.filelist_apk = []
self.filelist_zip = []
self.filelist_gzip = []
self.filelist_tar = []
self.filelist_rar = []
self.filelist_arsc = []
self.filelist_multimedia = []
self.filelist_other = [] #file type known but not managed
self.filelist_unknown = [] #file type unknown
# Lists of extensions used to detect changes
self.common_extensions = ["png","jpg","jpeg","gif","bmp","wav","ogg","mp3","ttf","zip"] # black list
self.elf_extensions = ["so","exe"] # white list
self.apk_extensions = ["apk","jar"] # white list
# Compiled regular expressions
self.re_script = {}
#SHELL_RISK
self.re_script[0] = re.compile(r"^(#!/.*)", re.IGNORECASE)
#SHELL_INSTALL_RISK
self.re_script[1] = re.compile(r"^(.*[^a-z0-9\n])?cp +.+ system/app/.*", re.IGNORECASE | re.MULTILINE)
self.re_script[2] = re.compile(r"^(.*[^a-z0-9\n])?pm +install[^a-z0-9\n].*", re.IGNORECASE | re.MULTILINE)
self.re_script[3] = re.compile(r"^(.*[^a-z0-9\n])?am +start[^a-z0-9\n].*", re.IGNORECASE | re.MULTILINE)
#SHELL_PRIVILEGE_RISK
self.re_script[4] = re.compile(r"^(.*[^a-z0-9\n])?(chown|chmod) +.*", re.IGNORECASE | re.MULTILINE)
self.re_script[5] = re.compile(r"^(.*[^a-z0-9\n])?mount +.* *remount+.*", re.IGNORECASE | re.MULTILINE)
self.re_script[6] = re.compile(r"^(.*[^a-z0-9\n])?(sudo|su +-c|system/bin/su) +.*", re.IGNORECASE | re.MULTILINE)
#SHELL_OTHER_RISK
self.re_script[7] = re.compile(r"(^.*[^a-z0-9\n])?setprop +.*", re.IGNORECASE | re.MULTILINE)
self.re_script[8] = re.compile(r"^(.*[^a-z0-9\n])?insmod .*", re.IGNORECASE | re.MULTILINE)
self.re_script[9] = re.compile(r"^.*system/bin/.*", re.IGNORECASE | re.MULTILINE)
self.re_script[10] = re.compile(r"^.* +resolv.conf.*", re.IGNORECASE | re.MULTILINE)
# Phone numbers
self.re_sms1 = re.compile(r"(tel:(//)?)?\+?[0-9]{4,}")
accepted_chars = r"[a-z0-9\.\-_~:\?#\[\]@!\$&\(\)\*\+=]|(?:%[0-9a-f]{2})" #/ ;'"
protocol = r'(?:https?|ftp|market):'
authentication = r'(?:('+accepted_chars+r')+(?::('+accepted_chars+r')*)?@)?'
# IP address dotted notation octets
# excludes loopback network 0.0.0.0, reserved space >= 224.0.0.0, network & broacast addresses (first & last IP address of each class)
regex1 = r'(?P<domain>(('+protocol+r'//)?'+authentication
regex1 += r'(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}'
regex1 += r'(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4])))|'
# URL
regex1 += r'((?:'+protocol+r'//|www\.)'+authentication+r'(?!\d+(?:\.\d+)+)('+accepted_chars+r')+'
# TLD identifier (http://data.iana.org/TLD/tlds-alpha-by-domain.txt)
regex1 += r'\.(?:([a-z]{2,6})|(xn--[a-z0-9]{4,18}))))'
# port number
regex1 += r'(?::\d{2,5})?'
# resource path
regex1 += r'(?:/('+accepted_chars+')+)?'
accepted_chars += r"|{[a-z0-9\.\-_~:\?#\[\]@!\$&\\\(\)\*\+=]+}|(?:%[0-9]+\$[a-z0-9,\+\-(#]+)"
# IP address dotted notation octets
# excludes loopback network 0.0.0.0, reserved space >= 224.0.0.0, network & broacast addresses (first & last IP address of each class)
regex2 = r'(?P<domain>('+protocol+r'\\?/\\?/?'+authentication
regex2 += r'(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\\?\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}'
regex2 += r'(?:\\?\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4])))|'
# URL
regex2 += r'((?:'+protocol+r'[\\]?/[\\]?/|www\\?\.)'+authentication+r'(?!\d+(?:\.\d+)+)('+accepted_chars+r'|[\\])+'
# TLD identifier (http://data.iana.org/TLD/tlds-alpha-by-domain.txt)
regex2 += r'\.(?:([a-z]{2,6})|(xn--[a-z0-9]{4,18}))))'
# port number
regex2 += r'(?::\d{2,5})?'
# resource path
regex2 += r'(?:/('+accepted_chars+'|[\\])*('+accepted_chars+')+)?'
# Regular URLs
self.re_url1 = re.compile(regex1, re.IGNORECASE)
#self.re_url1 = re.compile(r"((?:(https?|market|tel)://)|(?:www\.))(?:[a-z0-9-\._~:/\?#\[\]@!\$&'\(\)\*\+,;=]|(?:%[0-9a-f]{2}))+", re.IGNORECASE)
# Parametrical URLs
self.re_url2 = re.compile(regex2, re.IGNORECASE)
#self.re_url2 = re.compile(r"((?:(https?|market|tel):\\?/\\?/)|(?:www\.))(?:[a-z0-9-\._~:/\?#\[\]@!\$&'\(\)\*\+,;\\=]|(?:%[0-9a-f]{2})|{[a-z0-9-\._~:/\?#@!\$&'\+,;=]+})+", re.IGNORECASE)
# URLs to ignore
self.re_url_known = re.compile("(?:(?:(developer|schemas)\.android\.com)|(wc?3\.org)|(apple\.com/DTD)|(apache\.org)|(jquery\.com)|(developers\.facebook\.com))", re.IGNORECASE)
# Hashcodes of known infected binaries
self.known_infected_elf = {}
self.known_infected_elf["c4269275058f4f5239b45db88257df38c7d6cca2"] = "asroot-asroot-1"
self.known_infected_elf["a40181f2d912527af7371c490fbd36e48beb0d3f"] = "asroot-asroot-2"
self.known_infected_elf["63cbf4dff428a6743191a63d70b4d83970d4ee43"] = "basebridge-rageagainstthecage"
self.known_infected_elf["8d673db24815b1924c4fbff8f204c30e7570d4c2"] = "droiddream-exploid"
self.known_infected_elf["bc41b82ae83661906d7445b5cf451f21f278846a"] = "droiddream-rageagainstthecage"
self.known_infected_elf["38167159a4dd066ff525589183f8e68304fff2a6"] = "droidkungfu-kungfu"
self.known_infected_elf["c6908dc5f7c072d89d0f8359a0a2add9658b016a"] = "droidkungfulotoor"
self.known_infected_elf["611818ea2da9d302d6bcd9b61846d7fa9a65e96d"] = "gingermaster-gbfm.png"
self.known_infected_elf["f7db5b53aab5730351d23ccedaafa0bc776f08b6"] = "gingermaster-runme.png"
self.known_infected_elf["b703df668e41a8cf5bad44edf1ac65c915e5fe41"] = "zHash-lootor-extend"
self.known_infected_elf["28feffc93c1ec4e0cfd382b047a85c47dafec740"] = "zHash-lootor-zhash"
# Lists of data found during analysis, and their source files
self.urls = []
self.urls_domains = []
self.urls_files = []
self.urls2 = []
self.urls2_domains = []
self.urls2_files = []
self.numbers = []
self.numbers_files = []
self.scripts = []
self.scripts_files = []
# Time required by the analysis method
self.analysis_time = 0
# Risk values and script counts, saved during the analysis for later use
self.risks = {}
self.script_count = {
SHELL_RISK : 0,
SHELL_INSTALL_RISK : 0,
SHELL_PRIVILEGE_RISK : 0,
SHELL_OTHER_RISK : 0
}
file_data = ""
if raw==False :
self.path=file
file_data = open(file, 'rb').read()
else :
self.path=""
file_data = file
md5 = hashlib.md5()
sha1 = hashlib.sha1()
sha256 = hashlib.sha256()
md5.update(file_data)
sha1.update(file_data)
sha256.update(file_data)
self.checksum_md5 = md5.hexdigest()
self.checksum_sha1 = sha1.hexdigest()
self.checksum_sha256 = sha256.hexdigest()
try :
# Use a custom magic file
magic_descr = magic.Magic(magic_file="magic.mgc",mime=False)
magic_mime = magic.Magic(magic_file="magic.mgc",mime=True)
except Exception, e:
# If it is not available, use the default magic file of the system
magic_descr = magic.Magic(mime=False)
magic_mime = magic.Magic(mime=True)
if type=="zip" :
# APK/Zip/Jar archive
try :
if not raw :
zip = zipfile.ZipFile( file, mode="r" )
else :
fileobj = StringIO.StringIO(file)
zip = zipfile.ZipFile( fileobj, mode="r" )
except Exception, e :
# Typical errors:
# "unpack requires a string argument of length 4" see http://bugs.python.org/issue14315
# "File is not a zip file"
if not raw :
print "problem while opening file:" + file
raise e
for f in zip.namelist() :
try :
uncompressed_file = zip.read(f)
descr = magic_descr.from_buffer(uncompressed_file)
mime = magic_mime.from_buffer(uncompressed_file)
self._classify_file(mime, descr, uncompressed_file, f)
except Exception, e :
# Invalid file, skip it
pass
elif type=="gzip" :
# GZip archive
try:
gzip = __import__("gzip")
except ImportError:
raise Exception("Module gzip not found")
if not raw :
f = gzip.GzipFile(filename=file, mode='rb')
else :
f = gzip.GzipFile(mode='rb', fileobj=StringIO.StringIO(file) )
uncompressed_file = f.read()
f.close()
# Gzip archives contains a single file
descr = magic_descr.from_buffer(uncompressed_file)
mime = magic_mime.from_buffer(uncompressed_file)
self._classify_file(mime, descr, uncompressed_file, "(unknown)")
elif type=="tar" :
# Tar archive
try:
tarfile = __import__("tarfile")
except ImportError:
raise Exception("Module tarfile not found")
if not raw :
tar = tarfile.open(filename=file, mode='r')
else :
tar = tarfile.open(mode='r', fileobj=StringIO.StringIO(file) )
for f in tar.getnames() :
uncompressed_file = tar.extractfile(f).read()
descr = magic_descr.from_buffer(uncompressed_file)
mime = magic_mime.from_buffer(uncompressed_file)
self._classify_file(mime, descr, uncompressed_file, f)
tar.close()
elif type=="rar" :
# Rar archive
try:
rarfile = __import__("rarfile")
except ImportError:
raise Exception("Need to install module rarfile: http://rarfile.berlios.de/")
if not raw :
rar = rarfile.RarFile(file)
else :
tmp = open("tmp_filescan_rarfile.rar",'w')
tmp.write(file)
tmp.close()
rar = rarfile.RarFile( "tmp_filescan_rarfile.rar")
for f in rar.namelist() :
try :
uncompressed_file = rar.read(f)
descr = magic_descr.from_buffer(uncompressed_file)
mime = magic_mime.from_buffer(uncompressed_file)
self._classify_file(mime, descr, uncompressed_file, f.replace("\\","/"))
except Exception, e :
# Invalid file, skip it
pass
if raw :
os.remove("tmp_filescan_rarfile.rar")
else :
raise Exception("Unexpected archive type; supported values are \"zip\", \"gzip\", \"tar\" \"rar\"");
def _classify_file(self, file_mime, file_descr, file_raw, file_name="") :
"""
Analyze a file, checking its type
If it has an interesting format (eg. txt, dex, zip) memorize it.
If it has an unsupported format (eg. TTComp, LUA), memorize it without the raw data
If it has an uninteresting format (eg. PNG, ogg), skip it
@param file_mime : file mime type
@param file_descr : file type description
@param file_raw : file raw data
@param file_name : name of the file (if available)
"""
if not file_name=="" :
extension = os.path.splitext(file_name)[1][1:].lower()
else :
file_name = "(unknown)"
extension = "(unknown)"
self.files_types_descr[file_name] = file_descr
self.files_types_mime[file_name] = file_mime
mime_type = file_mime.partition("/")[0]
mime_subtype = file_mime.partition("/")[2].partition(";")[0]
if mime_type == "image" :
self.filelist_multimedia.append(file_name)
self._increment_type_count(self.TYPE_MULTIMEDIA)
elif mime_type == "application" :
if mime_subtype == "octet-stream" :
if "DBase" in file_descr and androconf.is_android_raw(file_raw) == "AXML" :
# Android's binary XML
self.filelist_other.append(file_name)
self._increment_type_count(self.TYPE_BINARY_XML)
elif file_descr.startswith("Dalvik dex") :
# Dalvik dex file
self.filelist_dex.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_DEX)
elif file_descr == "data" :
if extension == "arsc" :
# Compiled resources
self.filelist_arsc.append(file_name)
# Decompile and save the strings values
arscp = ARSCParser(file_raw)
self.files[file_name] = arscp.get_strings_resources()
self._increment_type_count(self.TYPE_ARSC)
else :
# Unknown binary format
self.filelist_unknown.append(file_name)
self._increment_type_count(self.TYPE_BINARY)
elif file_descr.startswith("Lua bytecode") :
# Lua bytecode
self.filelist_other.append(file_name)
self._increment_type_count(self.TYPE_OTHER)
elif file_descr.startswith("compiled Java") :
# compiled Java class data
self.filelist_other.append(file_name)
self._increment_type_count(self.TYPE_OTHER)
elif file_descr.startswith("Audio file") :
# Audio file with ID3 version
self.filelist_multimedia.append(file_name)
self._increment_type_count(self.TYPE_MULTIMEDIA)
elif file_descr.startswith("AppleDouble") :
# AppleDouble encoded Macintosh file
self.filelist_other.append(file_name)
self._increment_type_count(self.TYPE_OTHER)
elif file_descr.startswith("TTComp archive data") :
# TTComp archive data
self.filelist_other.append(file_name)
self._increment_type_count(self.TYPE_ARCHIVE)
else :
# Unknown binary format
self.filelist_unknown.append(file_name)
self._increment_type_count(self.TYPE_BINARY)
elif mime_subtype == "ogg" :
# should be harmless
self.filelist_multimedia.append(file_name)
self._increment_type_count(self.TYPE_MULTIMEDIA)
elif mime_subtype == "xml" :
self.filelist_xml.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_XML)
elif mime_subtype == "zip" :
if androconf.is_android_raw(file_raw) == "APK" and androconf.is_valid_android_raw(file_raw) :
self.filelist_apk.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_PACKAGE)
if self.apk_export_path != "" :
# save this embedded apk to the filesystem, in the specified directory
sha1 = hashlib.sha1()
sha1.update(file_raw)
checksum_sha1 = sha1.hexdigest()
try :
tmp = open(self.apk_export_path + checksum_sha1 + ".apk",'w')
tmp.write(file_raw)
tmp.close()
except Exception, e :
print "Exception while exporting embedded apk "+file_name+":", e
self._scan_archive(file_name,"zip")
else :
self.filelist_zip.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_ARCHIVE)
self._scan_archive(file_name,"zip")
elif mime_subtype == "x-gzip" :
self.filelist_gzip.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_ARCHIVE)
self._scan_archive(file_name,"gzip")
elif mime_subtype == "x-tar" :
self.filelist_tar.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_ARCHIVE)
self._scan_archive(file_name,"tar")
elif mime_subtype == "x-rar" or mime_subtype == "x-rar-compressed" :
self.filelist_rar.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_ARCHIVE)
self._scan_archive(file_name,"rar")
elif (mime_subtype == "x-gtar" \
or mime_subtype == "x-arc" \
or mime_subtype == "x-archive"):
self.filelist_other.append(file_name)
self._increment_type_count(self.TYPE_ARCHIVE)
elif mime_subtype == "x-sharedlib" :
# ELF 32-bit LSB shared object
self.filelist_elf.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_ELF)
elif mime_subtype == "x-executable" :
# ELF 32-bit LSB executable
self.filelist_elf.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_ELF)
elif mime_subtype == "x-font-ttf" :
# TrueType font data
self.filelist_other.append(file_name)
self._increment_type_count(self.TYPE_OTHER)
elif mime_subtype == "x-empty" :
self.filelist_other.append(file_name)
self._increment_type_count(self.TYPE_EMPTY)
else :
# unknown
self.filelist_unknown.append(file_name)
self._increment_type_count(self.TYPE_OTHER)
elif mime_type == "text":
# third most frequent mime_type
self.filelist_text.append(file_name)
self.files[file_name] = file_raw
self._increment_type_count(self.TYPE_TEXT)
elif mime_type == "audio" or mime_type == "video":
self.filelist_multimedia.append(file_name)
self._increment_type_count(self.TYPE_MULTIMEDIA)
def _increment_type_count(self, category) :
tot = 0
if category in self.types :
tot = self.types[category]
self.types[category] = tot + 1
def _scan_archive(self, file, type) :
"""
Recursively scan a compressed archive, by instantiating a new FileScan object
@param file : specify the name of the file
@param type : specify the archive format (zip, gzip, tar, rar)
"""
raw_file = self.files[file]
try :
file_scan = FileScan(file = raw_file, raw = True, type = type,
apk_export_path = self.apk_export_path,
ENABLE_NET_CONNECTION = self.enable_net_connection,
DEBUG_IGNORE_CMD = self.ignore_cmd,
DEBUG_IGNORE_URL = self.ignore_url,
DEBUG_IGNORE_SMS = self.ignore_sms)
self.files_compressed_filescan[file] = file_scan
except Exception :
# Invalid archive file, ignore it
pass
def get_sha1(self) :
return self.checksum_sha1
def get_analysis_time(self) :
return self.analysis_time
def analyze_files(self, relative_path="") :
"""
Return a value expressing the risk assigned to these files
@param relative_path : needed only by internal recursion
"""
self.analysis_time = 0
start = time()
risks = {
INFECTED_DEX_RISK : 0,
INFECTED_ELF_RISK : 0,
HIDDEN_APK_RISK : 0,
HIDDEN_ELF_RISK : 0,
HIDDEN_TXT_RISK : 0,
EMBEDDED_APK : 0,
SHELL_RISK : 0,
SHELL_INSTALL_RISK : 0,
SHELL_PRIVILEGE_RISK : 0,
SHELL_OTHER_RISK : 0
}
# Initialize the count of the shell script files
self.script_count[SHELL_RISK] = 0
self.script_count[SHELL_INSTALL_RISK] = 0
self.script_count[SHELL_PRIVILEGE_RISK] = 0
self.script_count[SHELL_OTHER_RISK] = 0
# Analyze every text file
for f in self.filelist_text :
self._analyze_file_readable(f)
for f in self.filelist_xml :
self._analyze_file_xml(f)
for f in self.filelist_arsc :
self._analyze_file_xml(f)
# Save the count of the shell script files
risks[SHELL_RISK] += self.script_count[SHELL_RISK]
risks[SHELL_INSTALL_RISK] += self.script_count[SHELL_INSTALL_RISK]
risks[SHELL_PRIVILEGE_RISK] += self.script_count[SHELL_PRIVILEGE_RISK]
risks[SHELL_OTHER_RISK] += self.script_count[SHELL_OTHER_RISK]
# Count the textual files whose extension is in a black list
# Count the elf binaries not in "lib/armeabi*" whose extension is not in a white list
# Count the apk files whose extension is not in a white list
suspect_files = self._suspect_files()
risks[HIDDEN_TXT_RISK]=len(suspect_files["txt"])
risks[HIDDEN_ELF_RISK]=len(suspect_files["elf"])
risks[HIDDEN_APK_RISK]=len(suspect_files["apk"])
# Count the embedded apk files
risks[EMBEDDED_APK] = len(self.filelist_apk)
# Look for known infected ELF
elf_infected=self.get_elf_infected(self._elf_checksum())
# Check the detection rate for ELF and DEX
for file,result in self.get_detection_rate(self._elf_checksum()).iteritems() :
if file in elf_infected :
result = 100
if result > 0 :
risks[INFECTED_ELF_RISK] += int(result)
for file,result in self.get_detection_rate(self._dex_checksum()).iteritems() :
risks[INFECTED_DEX_RISK] += int(result)
# Recursion on internal archives
for k, v in self.files_compressed_filescan.iteritems() :
relative_path=relative_path+k+"/"
internal_risks = v.analyze_files(relative_path)
risks[INFECTED_DEX_RISK] += internal_risks[INFECTED_DEX_RISK]
risks[INFECTED_ELF_RISK] += internal_risks[INFECTED_ELF_RISK]
risks[HIDDEN_APK_RISK] += internal_risks[HIDDEN_APK_RISK]
risks[HIDDEN_ELF_RISK] += internal_risks[HIDDEN_ELF_RISK]
risks[HIDDEN_TXT_RISK] += internal_risks[HIDDEN_TXT_RISK]
risks[EMBEDDED_APK] += internal_risks[EMBEDDED_APK]
risks[SHELL_RISK] += internal_risks[SHELL_RISK]
risks[SHELL_INSTALL_RISK] += internal_risks[SHELL_INSTALL_RISK]
risks[SHELL_PRIVILEGE_RISK] += internal_risks[SHELL_PRIVILEGE_RISK]
risks[SHELL_OTHER_RISK] += internal_risks[SHELL_OTHER_RISK]
self.analysis_time = time() - start
self.risks = risks
return risks
def get_risk_score(self) :
"""
Return the risk score computed with risks values collected by analyze_files()
"""
return int(RiskIndicator().get_risk(self.risks))
def _analyze_file_readable(self, file, raw=False) :
data = file
if raw == False :
data = self.files[file]
else :
file = "(unknown)"
if not self.ignore_cmd == True :
self._search_script(data, file)
if not self.ignore_url == True :
self._search_url(data, file)
if not self.ignore_sms == True :
self._search_sms(data, file)
def _analyze_file_xml(self, file, raw=False) :
data = file
if raw == False :
data = self.files[file]
if not self.ignore_url == True :
self._search_url(data, file)
if not self.ignore_sms == True :
self._search_sms(data, file)
def get_apk(self) :
list_apk = list(self.filelist_apk)
# Recursion on internal archives
for name, archive in self.files_compressed_filescan.iteritems() :
for internal in archive.get_apk() :
list_apk.append(str(name+"/"+internal))
return list_apk
def get_types_count(self) :
"""
Return a dictionary with the count (by type) of the files found in the archive
"""
types = dict(self.types)
# Recursion on internal archives
for archive, archive_fileScan in self.files_compressed_filescan.iteritems() :
archive_types = archive_fileScan.get_types_count()
for type, count in archive_types.iteritems() :
if type in types :
types[type] = types[type] + archive_types[type]
else :
types[type] = archive_types[type]
return types
def get_files_list(self) :
"""
Return a list of the files
"""
files = []
files += self.filelist_text
files += self.filelist_xml
files += self.filelist_dex
files += self.filelist_elf
files += self.filelist_multimedia
files += self.filelist_other
files += self.filelist_unknown
# Recursion on internal archives
for zip in self.filelist_zip :
files.append(zip)
internal_list = self.files_compressed_filescan[zip].get_files_list()
for f in internal_list :
files.append(zip + "/" + f)
for apk in self.filelist_apk :
files.append(apk)
internal_list = self.files_compressed_filescan[apk].get_files_list()
for f in internal_list :
files.append(apk + "/" + f)
for gzip in self.filelist_gzip :
files.append(gzip)
internal_list = self.files_compressed_filescan[gzip].get_files_list()
for f in internal_list :
files.append(gzip + "/" + f)
for tar in self.filelist_tar :
files.append(tar)
internal_list = self.files_compressed_filescan[tar].get_files_list()
for f in internal_list :
files.append(tar + "/" + f)
for rar in self.filelist_rar :
files.append(rar)
internal_list = self.files_compressed_filescan[rar].get_files_list()
for f in internal_list :
files.append(rar + "/" + f)
return files
def get_suspect_files(self) :
"""
Return a dictionary of all the interesting files (textual, compressed, compiled)
which have unusual extensions (not matching with their magic number)
"""
suspect_files = self._suspect_files()
# Recursion on internal archives
for k, v in self.files_compressed_filescan.iteritems() :
suspect = v.get_suspect_files()
for txt,descr in suspect["txt"].iteritems() :
suspect_files["txt"][k + "/" + txt] = descr
for txt,descr in suspect["elf"].iteritems() :
suspect_files["elf"][k + "/" + txt] = descr
for txt,descr in suspect["apk"].iteritems() :
suspect_files["apk"][k + "/" + txt] = descr
return suspect_files
def _suspect_files(self) :
"""
Return a dictionary of interesting files (textual, compressed, compiled)
which have unusual extensions (not matching with their magic number)
"""
suspect_files = {
"txt" : {},
"apk" : {},
"elf" : {}
}
for f in self.filelist_text :
ext = os.path.splitext(f)[1][1:].lower()
if (ext in self.common_extensions) :
suspect_files["txt"][f] = self.files_types_descr[f]
for f in self.filelist_elf :
ext = os.path.splitext(f)[1][1:].lower()
if (ext not in self.elf_extensions) :
if "lib/armeabi" not in f :
suspect_files["elf"][f] = self.files_types_descr[f]
for f in self.filelist_apk :
ext = os.path.splitext(f)[1][1:].lower()
if (ext not in self.apk_extensions) :
suspect_files["apk"][f] = self.files_types_descr[f]
return suspect_files
def get_dex_checksum(self,type="md5") :
"""
Return a dictionary that associate every dex file (recursively) to its checksum
@param type : hash functions used (md5, sha1, sha224, sha256, sha384, sha512)
"""
checksum = self._dex_checksum(type)
# Recursion on internal archives
for name, archive in self.files_compressed_filescan.iteritems() :
result = archive.get_dex_checksum(type)
for dex, hash in result.iteritems() :
checksum[name+"/"+dex] = hash
return checksum
def _dex_checksum(self,type="md5") :
"""
Return a dictionary that associate every dex file to its checksum
@param type : hash functions used (md5, sha1, sha224, sha256, sha384, sha512)
"""
checksum = {}
if type == "md5" :
hashobj = hashlib.md5()
elif type == "sha1" :
hashobj = hashlib.sha1()
elif type == "sha224" :
hashobj = hashlib.sha224()
elif type == "sha256" :
hashobj = hashlib.sha256()
elif type == "sha384" :
hashobj = hashlib.sha384()
elif type == "sha512" :
hashobj = hashlib.sha512()
else :
raise Exception("Unexpected value for parameter type in get_dex_checksum")
for f in self.filelist_dex :
m = hashobj.copy()
m.update(self.files[f])
checksum[f] = m.hexdigest()
return checksum
def get_elf_checksum(self,type="sha1") :
"""
Return a dictionary that associate every ELF file (recursively) to its checksum
@param type : hash functions used (md5, sha1, sha224, sha256, sha384, sha512)
"""
checksum = self._elf_checksum(type)
# Recursion on internal archives
for name, archive in self.files_compressed_filescan.iteritems() :
result = archive.get_elf_checksum(type)
for elf, hash in result.iteritems() :
checksum[name+"/"+elf] = hash
return checksum
def _elf_checksum(self,type="sha1") :
"""
Return a dictionary that associate every ELF file to its checksum
@param type : hash functions used (md5, sha1, sha224, sha256, sha384, sha512)
"""
checksum = {}
if type == "md5" :
hashobj = hashlib.md5()
elif type == "sha1" :
hashobj = hashlib.sha1()
elif type == "sha224" :
hashobj = hashlib.sha224()
elif type == "sha256" :
hashobj = hashlib.sha256()
elif type == "sha384" :
hashobj = hashlib.sha384()
elif type == "sha512" :
hashobj = hashlib.sha512()
else :
raise Exception("Unexpected value for parameter type in get_elf_checksum")
for f in self.filelist_elf :
m = hashobj.copy()
m.update(self.files[f])
checksum[f] = m.hexdigest()
return checksum
def _query_mhr(self, hash) :
"""
Handle a query to the Malware Hash Registry
http://www.team-cymru.org/Services/MHR/
@param hash : hashcode to check
"""
if self.enable_net_connection != True :
result = 0
else :
try :
FNULL = open('/dev/null', 'w')
p = subprocess.Popen("whois -h hash.cymru.com " + hash, \
stdout=subprocess.PIPE, \
stderr=FNULL, \
shell=True)
response = p.communicate()[0]
FNULL.close()
result = int(shlex.split(response)[2])
except :
result = 0
return result
def _is_mhr_reachable(self) :
"""
Test whether the whois service of hash.cymru.com is reachable
"""
result = self._query_mhr("cbed16069043a0bf3c92fff9a99cccdc")
if result == 0 :
return False
else :
return True
def get_detection_rate(self, files) :
"""
Return the detection rate for the files hashes
@param files : dictionary that associate file names to their hashcode
"""
detection_rate = {}
for file, hash in files.iteritems() :
detection_rate[file] = self._query_mhr(hash)
return detection_rate
def get_elf_infected(self, files) :
"""
Check if the ELF files are known malware
@param files : dictionary that associate file names to their hashcode
"""
elf_infected = {}
for file, hash in files.iteritems() :
if(hash in self.known_infected_elf) :
elf_infected[file] = self.known_infected_elf[hash]
return elf_infected
def get_scripts(self) :
"""
Return a list of lines identified as script commands,
found while performing method analyze_files(), and their source file
"""
scripts = self.scripts
scripts_files = self.scripts_files
# Recursion on internal archives
for name, archive in self.files_compressed_filescan.iteritems() :
s, sf = archive.get_scripts()
scripts.extend(s)
for file in sf :
scripts_files.append(name+"/"+file)
return (scripts, scripts_files)
def get_urls(self) :
"""
Return the URLs found while performing method analyze_files()
Return 3 lists of: complete URL, URL domain, and its source file
"""
urls = self.urls
domains = self.urls_domains
files = self.urls_files
# Recursion on internal archives
for name, archive in self.files_compressed_filescan.iteritems() :
u, d, f = archive.get_urls()
urls.extend(u)
domains.extend(d)
for file in f :
files.append(name+"/"+file)
return (urls, domains, files)
def get_urls_encoded(self) :
"""
Return a set of encoded URLs (with escape \ or parameters between {}),
found while performing method analyze_files()
Return 3 lists of: complete URL, URL domain, and its source file
"""
urls = self.urls2
domains = self.urls2_domains
files = self.urls2_files
# Recursion on internal archives
for name, archive in self.files_compressed_filescan.iteritems() :
u, d, f = archive.get_urls_encoded()
urls.extend(u)
domains.extend(d)
for file in f :
files.append(name+"/"+file)
return (urls, domains, files)
def get_numbers(self) :
"""
Return a set of phone numbers found while performing
the method analyze_files(), and their source file
"""
numbers = self.numbers
files = self.numbers_files
# Recursion on internal archives
for name, archive in self.files_compressed_filescan.iteritems() :
n, f = archive.get_numbers()
numbers.extend(n)
for file in f :
files.append(name+"/"+file)
return (numbers, files)
def _search_script(self, data, file) :
"""
Apply regular expressions looking for shell commands
@param data : text buffer
@param file : name of the file
"""
max_line_length = len(max(data.splitlines(), key=len))
if max_line_length > 5000 :
# line too long, dont search it
return
for regex_id, regex in self.re_script.iteritems() :
match = regex.finditer(data)
try :
while True :
m = match.next().group(0)
if m not in self.scripts : # Count every identical match only once
if regex_id == 0 :
self.script_count[SHELL_RISK]+=1
elif regex_id in [1,2,3] :
self.script_count[SHELL_INSTALL_RISK]+=1
elif regex_id in [4,5,6,7] :
self.script_count[SHELL_PRIVILEGE_RISK]+=1
elif regex_id in [8,9,10] :
self.script_count[SHELL_OTHER_RISK]+=1
self.scripts.append(m)
self.scripts_files.append(file)
except StopIteration, e :
pass
def _search_url(self, data, file) :
"""
Apply regular expression looking for url
"""
max_line_length = len(max(data.splitlines(), key=len))
if max_line_length > 10000 :
# line too long, dont search it
#print " file: "+file+" lines:%d"%(max_line_length)
return
#Valid URLs
match = self.re_url1.finditer(data)
while True :
try :
m = match.next()
m_tot = m.group(0)
m_domain = m.group("domain")
if (self.re_url_known.search(m_tot) is None
and m_tot not in self.urls) :
self.urls.append(m_tot)
self.urls_domains.append(m_domain)
self.urls_files.append(file)
except StopIteration, e :
break
#Parametrical and escaped URLs
match = self.re_url2.finditer(data)
while True :
try :
m = match.next()
m_tot = m.group(0)
m_domain = m.group("domain")
if (self.re_url_known.search(m_tot) is None
and m_tot not in self.urls
and m_tot not in self.urls2) :
self.urls2.append(m_tot)
self.urls2_domains.append(m_domain)
self.urls2_files.append(file)