├── test_data ├── ipl_5.bin ├── mbr_5.bin ├── disk_5.img ├── disk_60.img ├── disk_61.img ├── disk_62.img ├── disk_tc.img ├── ipl_60.bin ├── ipl_61.bin ├── ipl_62.bin ├── mbr_60.bin ├── mbr_61.bin ├── mbr_tc.bin ├── ipl_empty.bin ├── mbr_empty_code.bin ├── vbr_5_off_32256.bin ├── mbr_protect_uefi.bin ├── vbr_60_off_1048576.bin ├── vbr_61_off_1048576.bin ├── vbr_62_off_1048576.bin ├── vbr_61_bitlocker_off_525336576.bin ├── mbr_empty.bin └── vbr_empty.bin ├── tests ├── conftest.py ├── test_ipl.py ├── test_img.py ├── test_vbr.py └── test_mbr.py ├── data └── bootrecord_whitelist.csv ├── README.md ├── LICENSE └── bootcode_parser.py /test_data/ipl_5.bin: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/ANSSI-FR/bootcode_parser/HEAD/test_data/ipl_5.bin -------------------------------------------------------------------------------- /test_data/mbr_5.bin: 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-------------------------------------------------------------------------------- /tests/conftest.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env python2 2 | # -*- coding:utf-8 -*- 3 | 4 | from __future__ import unicode_literals 5 | import csv 6 | import os 7 | import pytest 8 | 9 | 10 | BOOTRECORD_WHITELIST_PATH = os.path.join(os.path.dirname(__file__), '..', 'data', 'bootrecord_whitelist.csv') 11 | 12 | 13 | @pytest.fixture(scope='module') 14 | def whitelist(request): 15 | lWhitelist = [] 16 | # CSV file content should be "Type,SHA256,Comment" 17 | with open(BOOTRECORD_WHITELIST_PATH, 'rb') as fd: 18 | reader = csv.DictReader(fd) 19 | for row in reader: 20 | lWhitelist.append(row) 21 | return lWhitelist 22 | 23 | -------------------------------------------------------------------------------- /data/bootrecord_whitelist.csv: -------------------------------------------------------------------------------- 1 | "Type","SHA256","Comment" 2 | "MBR","b5ed343494f0326a08aa6abf7cc9aa4d96207532cf0d2b39453c6eb7bede19e3","NT5.1/NT5.2 MBR" 3 | "MBR","4799e8c92d32bca8e5103110a322523adb7a3909324132bd9abab8f3345e094a","NT6.0 MBR" 4 | "MBR","088995559ab317af9b3291408da689651e8353f62e0a478d92eb0b5a947063fd","NT6.1+ MBR" 5 | "MBR","955ff28fdffd869e617dfc1d44a6a40b45005c5d76491069e06ad48817499fea","GRUB2 MBR" 6 | "MBR","e6e6605c48665800786de4651ade2893970aafb1237a06db0943a8603dd4fce1","TrueCrypt MBR" 7 | "MBR","8a029cf94efd555b34d5564cc5c8e290a6ba5a52b6cdf9f02253f0d939f4dcec","Safeboot MBR" 8 | "MBR","eedc57fa55ab1c71aa2fd511ff121e7d635b1e4bf7e7aeaa2a860360442790e1","Safeboot MBR" 9 | "VBR","5cb5aa385e0ada266690a2821e3a36ad372720d2ff47c0b1cd9d6ebcab25bf4e","NT5.1/NT5.2 VBR" 10 | "VBR","a1932aaba7d6d3adb1637e2ee0c8355706842ba825ea811728165420c518c0b1","NT6.0 VBR" 11 | "VBR","96d38c1be37b9124fb71d1d0f5c52969f0074687fe17aef0e1bafc54428674f6","NT6.1 VBR" 12 | "VBR","51643dcce7e93d795b08e1f19e38374ae4deaf3b1217527561a44aa9913ded23","NT6.2+ VBR" 13 | "VBR","47138cbe995a20483209270ef55693c8c8e85ca870f28789229ce421aded92b4","NT6.1+ Bitlocker VBR" 14 | "IPL","525788a688cfbe9e416122f0bc3cfb32ce9699fd12356b6ccaa173444c7d8f3f","NT5.1/NT5.2 IPL" 15 | "IPL","ff1aae04bac3e29f062a7fa17320d7d26363256a69f96840718d45301da71291","NT6.0 IPL" 16 | "IPL","462afe2322bad3d1c2747d7437d5f6c157e00ca37e5d38ebedd25346b3b488ce","NT6.1 IPL" 17 | "IPL","c09d496a1f24086c333468d58256d5db9c73fee945fca74603bdab05f19a6d57","NT6.2+ IPL" 18 | -------------------------------------------------------------------------------- /tests/test_ipl.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env python2 2 | # -*- coding:utf-8 -*- 3 | 4 | from __future__ import unicode_literals 5 | from bootcode_parser import InitialProgramLoader, InvalidIPLError 6 | import os 7 | import pytest 8 | 9 | 10 | def test_ipl_nt5_with_whitelist(whitelist): 11 | sampleName = os.path.join('test_data', 'ipl_5.bin') 12 | 13 | dParsed = {} 14 | dExpected = { 15 | 'record_type': 'IPL', 16 | 'sample_name': sampleName, 17 | 'partition_table': [], 18 | 'disk_signature': None, 19 | 'oem_id': None, 20 | 'code_SHA256': '525788a688cfbe9e416122f0bc3cfb32ce9699fd12356b6ccaa173444c7d8f3f'.decode('hex'), 21 | 'suspicious_behaviour': [], 22 | 'known_code_signature': ['NT5.1/NT5.2 IPL'], 23 | } 24 | with open(sampleName, 'rb') as f_ipl: 25 | objIPL = InitialProgramLoader(f_ipl, os.path.getsize(f_ipl.name), whitelist=whitelist) 26 | dParsed = objIPL.getDictRecord() 27 | dParsed.pop('record_raw') 28 | assert dParsed == dExpected 29 | 30 | 31 | def test_ipl_nt60_with_whitelist(whitelist): 32 | sampleName = os.path.join('test_data', 'ipl_60.bin') 33 | 34 | dParsed = {} 35 | dExpected = { 36 | 'record_type': 'IPL', 37 | 'sample_name': sampleName, 38 | 'partition_table': [], 39 | 'disk_signature': None, 40 | 'oem_id': None, 41 | 'code_SHA256': 'ff1aae04bac3e29f062a7fa17320d7d26363256a69f96840718d45301da71291'.decode('hex'), 42 | 'suspicious_behaviour': [], 43 | 'known_code_signature': ['NT6.0 IPL'], 44 | } 45 | with open(sampleName, 'rb') as f_ipl: 46 | objIPL = InitialProgramLoader(f_ipl, os.path.getsize(f_ipl.name), whitelist=whitelist) 47 | dParsed = objIPL.getDictRecord() 48 | dParsed.pop('record_raw') 49 | assert dParsed == dExpected 50 | 51 | 52 | def test_ipl_nt61_with_whitelist(whitelist): 53 | sampleName = os.path.join('test_data', 'ipl_61.bin') 54 | 55 | dParsed = {} 56 | dExpected = { 57 | 'record_type': 'IPL', 58 | 'sample_name': sampleName, 59 | 'partition_table': [], 60 | 'disk_signature': None, 61 | 'oem_id': None, 62 | 'code_SHA256': '462afe2322bad3d1c2747d7437d5f6c157e00ca37e5d38ebedd25346b3b488ce'.decode('hex'), 63 | 'suspicious_behaviour': [], 64 | 'known_code_signature': ['NT6.1 IPL'], 65 | } 66 | with open(sampleName, 'rb') as f_ipl: 67 | objIPL = InitialProgramLoader(f_ipl, os.path.getsize(f_ipl.name), whitelist=whitelist) 68 | dParsed = objIPL.getDictRecord() 69 | dParsed.pop('record_raw') 70 | assert dParsed == dExpected 71 | 72 | 73 | def test_ipl_nt62_with_whitelist(whitelist): 74 | sampleName = os.path.join('test_data', 'ipl_62.bin') 75 | 76 | dParsed = {} 77 | dExpected = { 78 | 'record_type': 'IPL', 79 | 'sample_name': sampleName, 80 | 'partition_table': [], 81 | 'disk_signature': None, 82 | 'oem_id': None, 83 | 'code_SHA256': 'c09d496a1f24086c333468d58256d5db9c73fee945fca74603bdab05f19a6d57'.decode('hex'), 84 | 'suspicious_behaviour': [], 85 | 'known_code_signature': ['NT6.2+ IPL'], 86 | } 87 | with open(sampleName, 'rb') as f_ipl: 88 | objIPL = InitialProgramLoader(f_ipl, os.path.getsize(f_ipl.name), whitelist=whitelist) 89 | dParsed = objIPL.getDictRecord() 90 | dParsed.pop('record_raw') 91 | assert dParsed == dExpected 92 | 93 | 94 | def test_ipl_empty_with_whitelist(whitelist): 95 | sampleName = os.path.join('test_data', 'ipl_empty.bin') 96 | 97 | with pytest.raises(InvalidIPLError) as e: 98 | with open(sampleName, 'rb') as f_ipl: 99 | objIPL = InitialProgramLoader(f_ipl, os.path.getsize(f_ipl.name), whitelist=whitelist) 100 | assert 'Invalid IPL structure: ' in str(e.value) 101 | 102 | 103 | def test_ipl_rovnix_with_whitelist(whitelist): 104 | sampleName = os.path.join('test_data', 'ipl_rovnix.bin') 105 | 106 | dParsed = {} 107 | dExpected = { 108 | 'record_type': 'IPL', 109 | 'sample_name': sampleName, 110 | 'partition_table': [], 111 | 'disk_signature': None, 112 | 'oem_id': None, 113 | 'code_SHA256': '51605476b580fd6e38b22cc0a2a2aad18102806117c45b70c73f39a6a93b7aed'.decode('hex'), 114 | 'suspicious_behaviour': ['Unknown Interrupt : 0x70'], 115 | 'known_code_signature': [], 116 | } 117 | with open(sampleName, 'rb') as f_ipl: 118 | objIPL = InitialProgramLoader(f_ipl, os.path.getsize(f_ipl.name), whitelist=whitelist) 119 | dParsed = objIPL.getDictRecord() 120 | dParsed.pop('record_raw') 121 | assert dParsed == dExpected 122 | 123 | -------------------------------------------------------------------------------- /tests/test_img.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env python2 2 | # -*- coding:utf-8 -*- 3 | 4 | from __future__ import unicode_literals 5 | from bootcode_parser import * 6 | import bootcode_parser 7 | import pytest 8 | import pytest_catchlog 9 | import os 10 | import logging 11 | 12 | 13 | def test_img_nt5_with_whitelist(caplog, whitelist): 14 | sampleName = os.path.join('test_data', 'disk_5.img') 15 | caplog.set_level(logging.INFO) 16 | with open(sampleName, 'rb') as f_img: 17 | parseImageFile(f_img, sectorSize=512, whitelist=whitelist) 18 | assert caplog.record_tuples == [ 19 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT5.1/NT5.2 MBR']"), 20 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT5.1/NT5.2 VBR']"), 21 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT5.1/NT5.2 IPL']") 22 | ] 23 | 24 | 25 | 26 | def test_img_nt60_with_whitelist(caplog, whitelist): 27 | sampleName = os.path.join('test_data', 'disk_60.img') 28 | caplog.set_level(logging.INFO) 29 | with open(sampleName, 'rb') as f_img: 30 | parseImageFile(f_img, sectorSize=512, whitelist=whitelist) 31 | assert caplog.record_tuples == [ 32 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.0 MBR']"), 33 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.0 VBR']"), 34 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.0 IPL']") 35 | ] 36 | 37 | 38 | def test_img_nt61_with_whitelist(caplog, whitelist): 39 | sampleName = os.path.join('test_data', 'disk_61.img') 40 | caplog.set_level(logging.INFO) 41 | with open(sampleName, 'rb') as f_img: 42 | parseImageFile(f_img, sectorSize=512, whitelist=whitelist) 43 | assert caplog.record_tuples == [ 44 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.1+ MBR']"), 45 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.1 VBR']"), 46 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.1 IPL']") 47 | ] 48 | 49 | 50 | def test_img_nt62_with_whitelist(caplog, whitelist): 51 | sampleName = os.path.join('test_data', 'disk_62.img') 52 | caplog.set_level(logging.INFO) 53 | with open(sampleName, 'rb') as f_img: 54 | parseImageFile(f_img, sectorSize=512, whitelist=whitelist) 55 | assert caplog.record_tuples == [ 56 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.1+ MBR']"), 57 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.2+ VBR']"), 58 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.2+ IPL']") 59 | ] 60 | 61 | 62 | def test_img_gapz_with_whitelist(caplog, whitelist): 63 | sampleName = os.path.join('test_data', 'disk_gapz.img') 64 | caplog.set_level(logging.INFO) 65 | with open(sampleName, 'rb') as f_img: 66 | parseImageFile(f_img, sectorSize=512, whitelist=whitelist) 67 | assert caplog.record_tuples[:-1] == [ 68 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.1+ MBR']"), 69 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT6.1 VBR']"), 70 | (bootcode_parser.__file__, logging.WARNING, "Suspicious behaviours were detected: [u'Suspicious HiddenSectors " 71 | "value: 209714414 (107373779968 bytes)']"), 72 | (bootcode_parser.__file__, logging.WARNING, "VBR of the active partition located at sector 2048 (offset " 73 | "1048576) is suspicious (see previous warning). This could mean " 74 | "that the partition table in the MBR or the BPB in the VBR has " 75 | "been tampered with !"), 76 | (bootcode_parser.__file__, logging.WARNING, "HiddenSectors value in BiosParameterBlock is different than actual" 77 | " offset in partition table ! HiddenSectors=209714414, partition" 78 | " table offset=2048"), 79 | ] 80 | name, level, msg = caplog.record_tuples[-1] 81 | assert (name, level) == (bootcode_parser.__file__, logging.ERROR) 82 | assert msg.startswith("Invalid IPL structure:") 83 | 84 | 85 | def test_img_rovnix_with_whitelist(caplog, whitelist): 86 | sampleName = os.path.join('test_data', 'disk_rovnix.img') 87 | caplog.set_level(logging.INFO) 88 | with open(sampleName, 'rb') as f_img: 89 | parseImageFile(f_img, sectorSize=512, whitelist=whitelist) 90 | assert caplog.record_tuples == [ 91 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT5.1/NT5.2 MBR']"), 92 | (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['NT5.1/NT5.2 VBR']"), 93 | (bootcode_parser.__file__, logging.WARNING, "No known code signature were found, this is highly suspicious."), 94 | (bootcode_parser.__file__, logging.WARNING, "Suspicious behaviours were detected: [u'Unknown Interrupt : 0x70']") 95 | ] 96 | 97 | 98 | def test_img_tc_with_whitelist(caplog, whitelist): 99 | sampleName = os.path.join('test_data', 'disk_tc.img') 100 | caplog.set_level(logging.INFO) 101 | with open(sampleName, 'rb') as f_img: 102 | parseImageFile(f_img, sectorSize=512, whitelist=whitelist) 103 | assert caplog.record_tuples[0] == (bootcode_parser.__file__, logging.INFO, "Known signatures found: ['TrueCrypt MBR']") 104 | assert caplog.records[1].levelno == logging.ERROR 105 | assert caplog.records[1].message.startswith("Invalid VBR structure:") 106 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | :warning: **This project is in maintenance mode: issues and PRs will still be addressed, but no further development will be made.** :warning: 2 | 3 | bootcode_parser 4 | ================= 5 | ```bootcode_parser.py``` is a Python script designed to perform a quick offline analysis of the boot records used by BIOS based systems (UEFI is *not* supported). 6 | 7 | It is intended to help the analyst triaging individual boot record dumps or whole disk images. 8 | The latter is preferred since it allows the script to perform additional checks that would not be possible on individual dumps alone. 9 | 10 | This script only detects anomalies that have to be manually investigated by an analyst. 11 | Because it works with a whitelist mechanism it will be able to detect a wide range of malicious codes, 12 | but it will also detect legitimate (encryption software, etc...) or benign modification of the boot records. 13 | 14 | This topic has been presented during a talk at the French conference CORI&IN 2017. 15 | 16 | How does it work ? 17 | ================== 18 | The script is based on the fact that boot records contain code sections that do not vary much from a machine to another. 19 | The differences can be identified and understood by performing a static analysis. 20 | 21 | This script merely implements the results of these analyses and tries to narrow down these "invariant" codes and hash them. 22 | The hash is then compared to a whitelist of known good signatures that has to be built by the analyst (an example is given, but it is advised to build its own). 23 | If no record is found in the whitelist then the boot record *must* be investigated by the analyst. 24 | In this case, static analysis is the only way to decide whether the boot record has been infected or not. 25 | 26 | How to interpret the results ? 27 | ============================== 28 | [INFO] messages mean the boot record was found in the whitelist 29 | 30 | [WARNING] messages mean the boot record or the boot sequence (when providing a whole disk image) needs to be investigated 31 | 32 | [ERROR] messages mean the script could not finish its operation, generally because the sample's structure could not be validated 33 | 34 | [DEBUG] messages (displayed with ```--logLevel DEBUG```) can be used to show internal details of the process of verification 35 | and display the newly calculated hash of an unknown boot record 36 | 37 | Dependencies 38 | ============ 39 | * python2 >= 2.7 40 | * python-construct == 2.8 41 | * python-capstone >= 3.0.4 42 | 43 | Usage 44 | ===== 45 | ``` 46 | usage: bootcode_parser.py [-h] --type {VBR,MBR,IPL,IMG} --input INPUT 47 | [INPUT ...] [--offset OFFSET] 48 | [--sector-size SECTOR_SIZE] [--whitelist WHITELIST] 49 | [--logLevel {DEBUG,INFO,WARNING,ERROR,CRITICAL}] 50 | 51 | Check boot records for known good signatures 52 | 53 | optional arguments: 54 | -h, --help show this help message and exit 55 | --type {VBR,MBR,IPL,IMG} 56 | Type of boot record: MBR, VBR or IPL. Or whole disk image. 57 | --input INPUT [INPUT ...] 58 | Input file(s) to check 59 | --offset OFFSET Offset in bytes at which the boot record was dumped. Required only for VBR. Without it, some heuristics to detect malicious VBR will not work. 60 | --sector-size SECTOR_SIZE 61 | Disk sector size in bytes. Only applies for disk image input. Defaults to 512. 62 | --whitelist WHITELIST 63 | CSV file containing whitelisted boot record signatures. Without it, the boot record will always be flagged as suspicious. Defaults to ./data/bootrecord_whitelist.csv 64 | --logLevel {DEBUG,INFO,WARNING,ERROR,CRITICAL} 65 | Show debug messages according to the level provided. 66 | ``` 67 | 68 | Examples 69 | ======== 70 | Usage with individual boot records 71 | ---------------------------------- 72 | 73 | * MBR from fresh installs of Windows XP, Vista and 7, empty MBR (completely empty or just the code section), protective MBR and TrueCrypt MBR 74 | 75 | ```shell 76 | python bootcode_parser.py --type MBR --input test_data/mbr_* 77 | ``` 78 | ``` 79 | INFO - [test_data/mbr_5.bin] [MBR] Known signatures found: ['NT5.1/5.2 MBR'] 80 | INFO - [test_data/mbr_60.bin] [MBR] Known signatures found: ['NT6.0 MBR'] 81 | INFO - [test_data/mbr_61.bin] [MBR] Known signatures found: ['NT6.1+ MBR'] 82 | ERROR - [test_data/mbr_empty.bin] [MBR] Invalid MBR structure: expected 'U\xaa', found '\x00\x00' 83 | 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 84 | [...] 85 | 000001F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 86 | WARNING - [test_data/mbr_empty_code.bin] [MBR] No known code signature were found, this is highly suspicious. 87 | WARNING - [test_data/mbr_empty_code.bin] [MBR] Suspicious behaviours were detected: [u'Code section is null'] 88 | INFO - [test_data/mbr_protect_uefi.bin] [MBR] Known signatures found: [u'Protective MBR', u'UEFI (no legacy boot code)'] 89 | INFO - [test_data/mbr_tc.bin] [MBR] Known signatures found: ['TrueCrypt MBR'] 90 | ``` 91 | 92 | * VBR from fresh installs of Windows Vista, 7 and 8 93 | 94 | ```shell 95 | python bootcode_parser.py --type VBR --offset $((2048*512)) --input test_data/vbr_*_off_$((2048*512)).bin 96 | ``` 97 | ``` 98 | INFO - [test_data/vbr_60_off_1048576.bin] [VBR] Known signatures found: ['NT6.0 VBR'] 99 | INFO - [test_data/vbr_61_off_1048576.bin] [VBR] Known signatures found: ['NT6.1 VBR'] 100 | INFO - [test_data/vbr_62_off_1048576.bin] [VBR] Known signatures found: ['NT6.2+ VBR'] 101 | ``` 102 | 103 | * VBR from a fresh install of Windows XP 104 | 105 | ```shell 106 | python bootcode_parser.py --type VBR --offset $((63*512)) --input test_data/vbr_*_off_$((63*512)).bin 107 | ``` 108 | ``` 109 | INFO - [test_data/vbr_5_off_32256.bin] [VBR] Known signatures found: ['NT5.1/NT5.2 VBR'] 110 | ``` 111 | 112 | * IPL from fresh installs of Windows XP, Vista, 7 and 8 113 | 114 | ```shell 115 | python bootcode_parser.py --type IPL --input test_data/ipl_* 116 | ``` 117 | ``` 118 | INFO - [test_data/ipl_5.bin] [IPL] Known signatures found: ['NT5.1/NT5.2 IPL'] 119 | INFO - [test_data/ipl_60.bin] [IPL] Known signatures found: ['NT6.0 IPL'] 120 | INFO - [test_data/ipl_61.bin] [IPL] Known signatures found: ['NT6.1 IPL'] 121 | INFO - [test_data/ipl_62.bin] [IPL] Known signatures found: ['NT6.2+ IPL'] 122 | ``` 123 | 124 | Usage with whole disk images 125 | ---------------------------- 126 | * Fresh install of Windows 7 127 | 128 | ```shell 129 | python bootcode_parser.py --input clean_win7.dd --type IMG 130 | ``` 131 | ``` 132 | INFO - [/dev/storage/VM-Win7] Known signatures found: ['NT6.1+ MBR'] 133 | INFO - [/dev/storage/VM-Win7] Known signatures found: ['NT6.1 VBR'] 134 | INFO - [/dev/storage/VM-Win7] Known signatures found: ['NT6.1 IPL'] 135 | ``` 136 | 137 | * Windows XP infected with Gapz 138 | 139 | ```shell 140 | python bootcode_parser.py --input infected_with_gapz.dd --type IMG 141 | ``` 142 | ``` 143 | INFO - [infected_with_gapz.dd] [MBR] Known signatures found: ['NT5.1/5.2 MBR'] 144 | INFO - [infected_with_gapz.dd] [VBR] Known signatures found: ['NT5.1/NT5.2 VBR'] 145 | WARNING - [infected_with_gapz.dd] [VBR] Suspicious behaviours were detected: [u'Suspicious HiddenSectors value: 41942254 (21474434048 bytes)'] 146 | WARNING - [infected_with_gapz.dd] [VBR] VBR of the active partition located at sector 63 (offset 32256) is suspicious (see previous warning). This could mean that the partition table in the MBR or the BPB in the VBR has been tampered with ! 147 | WARNING - [infected_with_gapz.dd] [IMG] HiddenSectors value in BiosParameterBlock is different than actual offset in partition table ! HiddenSectors=41942254, partition table offset=63 148 | ERROR - [infected_with_gapz.dd] [IMG] Invalid IPL structure: expected 74016, found 7678 149 | 00000000: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 |................| 150 | [...] 151 | 000001F0: 90 90 90 90 90 90 90 90 90 90 90 90 eb 49 55 aa |.............IU.| 152 | ``` 153 | 154 | * Windows XP infected with Rovnix 155 | 156 | ```shell 157 | python bootcode_parser.py --input infected_with_rovnix.dd --type IMG 158 | ``` 159 | ``` 160 | INFO - [infected_with_rovnix.dd] [MBR] Known signatures found: ['NT5.1/5.2 MBR'] 161 | INFO - [infected_with_rovnix.dd] [VBR] Known signatures found: ['NT5.1/NT5.2 VBR'] 162 | WARNING - [infected_with_rovnix.dd] [IPL] No known code signature were found, this is highly suspicious. 163 | WARNING - [infected_with_rovnix.dd] [IPL] Suspicious behaviours were detected: [u'Unknown Interrupt : 0x70'] 164 | ``` 165 | -------------------------------------------------------------------------------- /tests/test_vbr.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env python2 2 | # -*- coding:utf-8 -*- 3 | 4 | from __future__ import unicode_literals 5 | from bootcode_parser import VolumeBootRecord, InvalidVBRError 6 | import os 7 | import pytest 8 | 9 | 10 | def test_vbr_nt5_with_whitelist(whitelist): 11 | sampleName = os.path.join('test_data', 'vbr_5_off_32256.bin') 12 | 13 | dParsed = {} 14 | dExpected = { 15 | 'record_type': 'VBR', 16 | 'sample_name': sampleName, 17 | 'partition_table': [], 18 | 'disk_signature': None, 19 | 'oem_id': 'NTFS ', 20 | 'code_SHA256': '5cb5aa385e0ada266690a2821e3a36ad372720d2ff47c0b1cd9d6ebcab25bf4e'.decode('hex'), 21 | 'record_raw': 'eb52904e5446532020202000020800000000000000f800003f00ff003f0000000000000080008000d7845f0400000000' 22 | '00000c00000000004df8450000000000f6000000010000000e11dfc051dfc0bc00000000fa33c08ed0bc007cfbb8c007' 23 | '8ed8e81600b8000d8ec033dbc6060e0010e8530068000d686a02cb8a162400b408cd137305b9ffff8af1660fb6c64066' 24 | '0fb6d180e23ff7e286cdc0ed0641660fb7c966f7e166a32000c3b441bbaa558a162400cd13720f81fb55aa7509f6c101' 25 | '7404fe061400c366601e0666a110006603061c00663b0620000f823a001e666a0066500653666810000100803e140000' 26 | '0f850c00e8b3ff803e1400000f846100b4428a162400161f8bf4cd1366585b07665866581feb2d6633d2660fb70e1800' 27 | '66f7f1fec28aca668bd066c1ea10f7361a0086d68a1624008ae8c0e4060accb80102cd130f8219008cc00520008ec066' 28 | 'ff061000ff0e0e000f856fff071f6661c3a0f801e80900a0fb01e80300fbebfeb4018bf0ac3c007409b40ebb0700cd10' 29 | 'ebf2c30d0a4572722e206c65637475726520646973717565000d0a4e544c4452206d616e717565000d0a4e544c445220' 30 | '65737420636f6d707265737382000d0a456e7472657a204374726c2b416c742b537570707220706f757220726564826d' 31 | '61727265720d0a000d0a00000000000000000000000000008399a8be000055aa'.decode('hex'), 32 | 'suspicious_behaviour': [], 33 | 'known_code_signature': ['NT5.1/NT5.2 VBR'], 34 | } 35 | with open(sampleName, 'rb') as f_mbr: 36 | objVBR = VolumeBootRecord(f_mbr, os.path.getsize(f_mbr.name), offset=32256, whitelist=whitelist) 37 | dParsed = objVBR.getDictRecord() 38 | assert dParsed == dExpected 39 | 40 | 41 | def test_vbr_nt60_with_whitelist(whitelist): 42 | sampleName = os.path.join('test_data', 'vbr_60_off_1048576.bin') 43 | 44 | dParsed = {} 45 | dExpected = { 46 | 'record_type': 'VBR', 47 | 'sample_name': sampleName, 48 | 'partition_table': [], 49 | 'disk_signature': None, 50 | 'oem_id': 'NTFS ', 51 | 'code_SHA256': 'a1932aaba7d6d3adb1637e2ee0c8355706842ba825ea811728165420c518c0b1'.decode('hex'), 52 | 'record_raw': 'eb52904e5446532020202000020800000000000000f800003f00ff00000800000000000080008000ffefdf0100000000' 53 | '00000c0000000000fffe1d0000000000f600000001000000acbf151cf6151c2800000000fa33c08ed0bc007cfb68c007' 54 | '1f1e686600cb88160e0066813e03004e5446537515b441bbaa55cd13720c81fb55aa7506f7c101007503e9d2001e83ec' 55 | '18681a00b4488a160e008bf4161fcd139f83c4189e581f72e13b060b0075dba30f00c12e0f00041e5a33dbb900202bc8' 56 | '66ff06110003160f008ec2ff061600e840002bc877efb800bbcd1a6623c0752d6681fb54435041752481f90201721e16' 57 | '6807bb1668700e1668090066536653665516161668b80166610e07cd1ae96a01909066601e0666a111006603061c001e' 58 | '66680000000066500653680100681000b4428a160e00161f8bf4cd1366595b5a665966591f0f82160066ff0611000316' 59 | '0f008ec2ff0e160075bc071f6661c3a0f801e80800a0fb01e80200ebfeb4018bf0ac3c007409b40ebb0700cd10ebf2c3' 60 | '0d0a41206469736b2072656164206572726f72206f63637572726564000d0a424f4f544d4752206973206d697373696e' 61 | '67000d0a424f4f544d475220697320636f6d70726573736564000d0a5072657373204374726c2b416c742b44656c2074' 62 | '6f20726573746172740d0a00000000000000000000000000809db2ca000055aa'.decode('hex'), 63 | 'suspicious_behaviour': [], 64 | 'known_code_signature': ['NT6.0 VBR'], 65 | } 66 | with open(sampleName, 'rb') as f_mbr: 67 | objVBR = VolumeBootRecord(f_mbr, os.path.getsize(f_mbr.name), offset=1048576, whitelist=whitelist) 68 | dParsed = objVBR.getDictRecord() 69 | assert dParsed == dExpected 70 | 71 | 72 | def test_vbr_nt61_with_whitelist(whitelist): 73 | sampleName = os.path.join('test_data', 'vbr_61_off_1048576.bin') 74 | 75 | dParsed = {} 76 | dExpected = { 77 | 'record_type': 'VBR', 78 | 'sample_name': sampleName, 79 | 'partition_table': [], 80 | 'disk_signature': None, 81 | 'oem_id': 'NTFS ', 82 | 'code_SHA256': '96d38c1be37b9124fb71d1d0f5c52969f0074687fe17aef0e1bafc54428674f6'.decode('hex'), 83 | 'record_raw': 'eb52904e5446532020202000020800000000000000f800003f00ff00000800000000000080008000ff1f030000000000' 84 | '55210000000000000200000000000000f6000000010000003231dc285edc286400000000fa33c08ed0bc007cfb68c007' 85 | '1f1e686600cb88160e0066813e03004e5446537515b441bbaa55cd13720c81fb55aa7506f7c101007503e9dd001e83ec' 86 | '18681a00b4488a160e008bf4161fcd139f83c4189e581f72e13b060b0075dba30f00c12e0f00041e5a33dbb900202bc8' 87 | '66ff06110003160f008ec2ff061600e84b002bc877efb800bbcd1a6623c0752d6681fb54435041752481f90201721e16' 88 | '6807bb1668700e1668090066536653665516161668b80166610e07cd1a33c0bf2810b9d80ffcf3aae95f01909066601e' 89 | '0666a111006603061c001e66680000000066500653680100681000b4428a160e00161f8bf4cd1366595b5a665966591f' 90 | '0f82160066ff06110003160f008ec2ff0e160075bc071f6661c3a0f801e80900a0fb01e80300f4ebfdb4018bf0ac3c00' 91 | '7409b40ebb0700cd10ebf2c30d0a41206469736b2072656164206572726f72206f63637572726564000d0a424f4f544d' 92 | '4752206973206d697373696e67000d0a424f4f544d475220697320636f6d70726573736564000d0a5072657373204374' 93 | '726c2b416c742b44656c20746f20726573746172740d0a008ca9bed6000055aa'.decode('hex'), 94 | 'suspicious_behaviour': [], 95 | 'known_code_signature': ['NT6.1 VBR'], 96 | } 97 | with open(sampleName, 'rb') as f_mbr: 98 | objVBR = VolumeBootRecord(f_mbr, os.path.getsize(f_mbr.name), offset=1048576, whitelist=whitelist) 99 | dParsed = objVBR.getDictRecord() 100 | assert dParsed == dExpected 101 | 102 | 103 | def test_vbr_nt61_bitlocker_with_whitelist(whitelist): 104 | sampleName = os.path.join('test_data', 'vbr_61_bitlocker_off_525336576.bin') 105 | 106 | dParsed = {} 107 | dExpected = { 108 | 'record_type': 'VBR', 109 | 'sample_name': sampleName, 110 | 'partition_table': [], 111 | 'disk_signature': None, 112 | 'oem_id': '-FVE-FS-', 113 | 'code_SHA256': '47138cbe995a20483209270ef55693c8c8e85ca870f28789229ce421aded92b4'.decode('hex'), 114 | 'record_raw': 'eb58902d4656452d46532d00020800000000000000f800003f00ff0000a80f0000000000e01f00000000000000000000' 115 | '01000600000000000000000000000000800029000000004e4f204e414d4520202020464154333220202033c98ed1bcf4' 116 | '7b8ec18ed9bd007ca0fb7db47d8bf0ac9840740c48740eb40ebb0700cd10ebefa0fd7debe6cd16cd1900000000000000' 117 | '000000000000000000000000000000003bd66749292ed84a8399f6a339e3d0010060cb0f000000000000504900000000' 118 | '008024bc0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 119 | '000000000000000000000000000000000d0a52656d6f7665206469736b73206f72206f74686572206d656469612eff0d' 120 | '0a4469736b206572726f72ff0d0a507265737320616e79206b657920746f20726573746172740d0a0000000000000000' 121 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 122 | '000000000000000000000000000000000000000000000000787878787878787878787878787878787878787878787878' 123 | '787878787878787878787878787878787878787878787878787878787878787878787878787878787878787878787878' 124 | '7878787878787878ffffffffffffffffffffffffffffffffffffff001f2c55aa'.decode('hex'), 125 | 'suspicious_behaviour': [], 126 | 'known_code_signature': ['NT6.1+ Bitlocker VBR'], 127 | } 128 | with open(sampleName, 'rb') as f_mbr: 129 | objVBR = VolumeBootRecord(f_mbr, os.path.getsize(f_mbr.name), offset=525336576, whitelist=whitelist) 130 | dParsed = objVBR.getDictRecord() 131 | assert dParsed == dExpected 132 | 133 | 134 | def test_vbr_nt62_with_whitelist(whitelist): 135 | sampleName = os.path.join('test_data', 'vbr_62_off_1048576.bin') 136 | 137 | dParsed = {} 138 | dExpected = { 139 | 'record_type': 'VBR', 140 | 'sample_name': sampleName, 141 | 'partition_table': [], 142 | 'disk_signature': None, 143 | 'oem_id': 'NTFS ', 144 | 'code_SHA256': '51643dcce7e93d795b08e1f19e38374ae4deaf3b1217527561a44aa9913ded23'.decode('hex'), 145 | 'record_raw': 'eb52904e5446532020202000020800000000000000f800003f00ff00000800000000000080008000ff0f0e0000000000' 146 | '00960000000000000200000000000000f600000001000000f8c2981acf981a4000000000fa33c08ed0bc007cfb68c007' 147 | '1f1e686600cb88160e0066813e03004e5446537515b441bbaa55cd13720c81fb55aa7506f7c101007503e9dd001e83ec' 148 | '18681a00b4488a160e008bf4161fcd139f83c4189e581f72e13b060b0075dba30f00c12e0f00041e5a33dbb900202bc8' 149 | '66ff06110003160f008ec2ff061600e84b002bc877efb800bbcd1a6623c0752d6681fb54435041752481f90201721e16' 150 | '6807bb166852111668090066536653665516161668b80166610e07cd1a33c0bf0a13b9f60cfcf3aae9fe01909066601e' 151 | '0666a111006603061c001e66680000000066500653680100681000b4428a160e00161f8bf4cd1366595b5a665966591f' 152 | '0f82160066ff06110003160f008ec2ff0e160075bc071f6661c3a1f601e80900a1fa01e80300f4ebfd8bf0ac3c007409' 153 | 'b40ebb0700cd10ebf2c30d0a41206469736b2072656164206572726f72206f63637572726564000d0a424f4f544d4752' 154 | '20697320636f6d70726573736564000d0a5072657373204374726c2b416c742b44656c20746f20726573746172740d0a' 155 | '000000000000000000000000000000000000000000008a01a701bf01000055aa'.decode('hex'), 156 | 'suspicious_behaviour': [], 157 | 'known_code_signature': ['NT6.2+ VBR'], 158 | } 159 | with open(sampleName, 'rb') as f_mbr: 160 | objVBR = VolumeBootRecord(f_mbr, os.path.getsize(f_mbr.name), offset=1048576, whitelist=whitelist) 161 | dParsed = objVBR.getDictRecord() 162 | assert dParsed == dExpected 163 | 164 | 165 | def test_vbr_empty_with_whitelist(whitelist): 166 | sampleName = os.path.join('test_data', 'mbr_empty.bin') 167 | 168 | with pytest.raises(InvalidVBRError) as e: 169 | with open(sampleName, 'rb') as f_vbr: 170 | objMBR = VolumeBootRecord(f_vbr, os.path.getsize(f_vbr.name), offset=1048576, whitelist=whitelist) 171 | assert 'Invalid VBR structure: ' in str(e.value) 172 | 173 | 174 | def test_vbr_gapz_with_whitelist(whitelist): 175 | sampleName = os.path.join('test_data', 'vbr_gapz_off_1048576.bin') 176 | 177 | dParsed = {} 178 | dExpected = { 179 | 'record_type': 'VBR', 180 | 'sample_name': sampleName, 181 | 'partition_table': [], 182 | 'disk_signature': None, 183 | 'oem_id': 'NTFS ', 184 | 'code_SHA256': '96d38c1be37b9124fb71d1d0f5c52969f0074687fe17aef0e1bafc54428674f6'.decode('hex'), 185 | 'record_raw': 'eb52904e5446532020202000020800000000000000f800003f00ff00eefc7f0c0000000080008000ff1f030000000000' 186 | '55210000000000000200000000000000f600000001000000b83d71846071849c00000000fa33c08ed0bc007cfb68c007' 187 | '1f1e686600cb88160e0066813e03004e5446537515b441bbaa55cd13720c81fb55aa7506f7c101007503e9dd001e83ec' 188 | '18681a00b4488a160e008bf4161fcd139f83c4189e581f72e13b060b0075dba30f00c12e0f00041e5a33dbb900202bc8' 189 | '66ff06110003160f008ec2ff061600e84b002bc877efb800bbcd1a6623c0752d6681fb54435041752481f90201721e16' 190 | '6807bb1668700e1668090066536653665516161668b80166610e07cd1a33c0bf2810b9d80ffcf3aae95f01909066601e' 191 | '0666a111006603061c001e66680000000066500653680100681000b4428a160e00161f8bf4cd1366595b5a665966591f' 192 | '0f82160066ff06110003160f008ec2ff0e160075bc071f6661c3a0f801e80900a0fb01e80300f4ebfdb4018bf0ac3c00' 193 | '7409b40ebb0700cd10ebf2c30d0a41206469736b2072656164206572726f72206f63637572726564000d0a424f4f544d' 194 | '4752206973206d697373696e67000d0a424f4f544d475220697320636f6d70726573736564000d0a5072657373204374' 195 | '726c2b416c742b44656c20746f20726573746172740d0a008ca9bed6000055aa'.decode('hex'), 196 | 'suspicious_behaviour': ['Suspicious HiddenSectors value: 209714414 (107373779968 bytes)'], 197 | 'known_code_signature': ['NT6.1 VBR'], 198 | } 199 | with open(sampleName, 'rb') as f_mbr: 200 | objVBR = VolumeBootRecord(f_mbr, os.path.getsize(f_mbr.name), offset=32256, whitelist=whitelist) 201 | dParsed = objVBR.getDictRecord() 202 | assert dParsed == dExpected 203 | 204 | -------------------------------------------------------------------------------- /tests/test_mbr.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env python2 2 | # -*- coding:utf-8 -*- 3 | 4 | from __future__ import unicode_literals 5 | from bootcode_parser import MasterBootRecord, InvalidMBRError 6 | import os 7 | import pytest 8 | 9 | 10 | def test_mbr_nt5_with_whitelist(whitelist): 11 | sampleName = os.path.join('test_data', 'mbr_5.bin') 12 | 13 | dParsed = {} 14 | dExpected = { 15 | 'record_type': 'MBR', 16 | 'sample_name': sampleName, 17 | 'partition_table': [{'Number': 1, 'Attributes': 'Active', 'Type': 'NTFS', 18 | 'Start sector': 63, 'Size in sectors': 73368792}], 19 | 'disk_signature': '059c059c'.decode('hex'), 20 | 'oem_id': None, 21 | 'code_SHA256': 'b5ed343494f0326a08aa6abf7cc9aa4d96207532cf0d2b39453c6eb7bede19e3'.decode('hex'), 22 | 'record_raw': '33c08ed0bc007cfb5007501ffcbe1b7cbf1b065057b9e501f3a4cbbdbe07b104386e007c09751383c510e2f4cd188bf5' 23 | '83c610497419382c74f6a0b507b4078bf0ac3c0074fcbb0700b40ecd10ebf2884e10e84600732afe4610807e040b740b' 24 | '807e040c7405a0b60775d2804602068346080683560a00e821007305a0b607ebbc813efe7d55aa740b807e100074c8a0' 25 | 'b707eba98bfc1e578bf5cbbf05008a5600b408cd1372238ac1243f988ade8afc43f7e38bd186d6b106d2ee42f7e23956' 26 | '0a77237205394608731cb80102bb007c8b4e028b5600cd1373514f744e32e48a5600cd13ebe48a560060bbaa55b441cd' 27 | '13723681fb55aa7530f6c101742b61606a006a00ff760aff76086a0068007c6a016a10b4428bf4cd136161730e4f740b' 28 | '32e48a5600cd13ebd661f9c35461626c6520646520706172746974696f6e206e6f6e2076616c69646500457272657572' 29 | '206c6f7273206475206368617267656d656e7420647520737973748a6d652064276578706c6f69746174690053797374' 30 | '8a6d652064276578706c6f69746174696f6e20616273656e740000000000000000000000000000000000000000000000' 31 | '00000000002c4a7c059c059c00008001010007feffff3f000000d8845f04000000000000000000000000000000000000' 32 | '00000000000000000000000000000000000000000000000000000000000055aa'.decode('hex'), 33 | 'suspicious_behaviour': [], 34 | 'known_code_signature': ['NT5.1/NT5.2 MBR'], 35 | } 36 | with open(sampleName, 'rb') as f_mbr: 37 | objMBR = MasterBootRecord(f_mbr, os.path.getsize(f_mbr.name), whitelist=whitelist) 38 | dParsed = objMBR.getDictRecord() 39 | assert dParsed == dExpected 40 | 41 | 42 | def test_mbr_nt60_with_whitelist(whitelist): 43 | sampleName = os.path.join('test_data', 'mbr_60.bin') 44 | 45 | dParsed = {} 46 | dExpected = { 47 | 'record_type': 'MBR', 48 | 'sample_name': sampleName, 49 | 'partition_table': [{'Number': 1, 'Attributes': 'Active', 'Type': 'NTFS', 50 | 'Start sector': 2048, 'Size in sectors': 41938944}], 51 | 'disk_signature': 'c9eda2df'.decode('hex'), 52 | 'oem_id': None, 53 | 'code_SHA256': '4799e8c92d32bca8e5103110a322523adb7a3909324132bd9abab8f3345e094a'.decode('hex'), 54 | 'record_raw': '33c08ed0bc007c8ec08ed8be007cbf0006b90002fcf3a450681c06cbfbb90400bdbe07807e00007c0b0f85100183c510' 55 | 'e2f1cd1888560055c6461105c6461000b441bbaa55cd135d720f81fb55aa7509f7c101007403fe46106660807e100074' 56 | '2666680000000066ff760868000068007c680100681000b4428a56008bf4cd139f83c4109eeb14b80102bb007c8a5600' 57 | '8a76018a4e028a6e03cd136661731efe4e110f850c00807e00800f848a00b280eb825532e48a5600cd135deb9c813efe' 58 | '7d55aa756eff7600e88a000f851500b0d1e664e87f00b0dfe660e87800b0ffe664e87100b800bbcd1a6623c0753b6681' 59 | 'fb54435041753281f90201722c666807bb00006668000200006668080000006653665366556668000000006668007c00' 60 | '00666168000007cd1a5a32f6ea007c0000cd18a0b707eb08a0b607eb03a0b50732e40500078bf0ac3c0074fcbb0700b4' 61 | '0ecd10ebf22bc9e464eb002402e0f82402c3496e76616c696420706172746974696f6e207461626c65004572726f7220' 62 | '6c6f6164696e67206f7065726174696e672073797374656d004d697373696e67206f7065726174696e67207379737465' 63 | '6d00000000627a99c9eda2df00008020210007feffff0008000000f07f02000000000000000000000000000000000000' 64 | '00000000000000000000000000000000000000000000000000000000000055aa'.decode('hex'), 65 | 'suspicious_behaviour': [], 66 | 'known_code_signature': ['NT6.0 MBR'], 67 | } 68 | with open(sampleName, 'rb') as f_mbr: 69 | objMBR = MasterBootRecord(f_mbr, os.path.getsize(f_mbr.name), whitelist=whitelist) 70 | dParsed = objMBR.getDictRecord() 71 | assert dParsed == dExpected 72 | 73 | 74 | def test_mbr_nt61_with_whitelist(whitelist): 75 | sampleName = os.path.join('test_data', 'mbr_61.bin') 76 | 77 | dParsed = {} 78 | dExpected = { 79 | 'record_type': 'MBR', 80 | 'sample_name': sampleName, 81 | 'partition_table': [{'Number': 1, 'Attributes': 'Active', 'Type': 'NTFS', 82 | 'Start sector': 2048, 'Size in sectors': 204800}, 83 | {'Number': 2, 'Attributes': 'Inactive', 'Type': 'NTFS', 84 | 'Start sector': 206848, 'Size in sectors': 40685568}, 85 | {'Number': 3, 'Attributes': 'Inactive', 'Type': 'NTFS', 86 | 'Start sector': 40892416, 'Size in sectors': 1046528}, 87 | ], 88 | 'disk_signature': '14a90642'.decode('hex'), 89 | 'oem_id': None, 90 | 'code_SHA256': '088995559ab317af9b3291408da689651e8353f62e0a478d92eb0b5a947063fd'.decode('hex'), 91 | 'record_raw': '33c08ed0bc007c8ec08ed8be007cbf0006b90002fcf3a450681c06cbfbb90400bdbe07807e00007c0b0f850e0183c510' 92 | 'e2f1cd1888560055c6461105c6461000b441bbaa55cd135d720f81fb55aa7509f7c101007403fe46106660807e100074' 93 | '2666680000000066ff760868000068007c680100681000b4428a56008bf4cd139f83c4109eeb14b80102bb007c8a5600' 94 | '8a76018a4e028a6e03cd136661731cfe4e11750c807e00800f848a00b280eb845532e48a5600cd135deb9e813efe7d55' 95 | 'aa756eff7600e88d007517fab0d1e664e88300b0dfe660e87c00b0ffe664e87500fbb800bbcd1a6623c0753b6681fb54' 96 | '435041753281f90201722c666807bb00006668000200006668080000006653665366556668000000006668007c000066' 97 | '6168000007cd1a5a32f6ea007c0000cd18a0b707eb08a0b607eb03a0b50732e40500078bf0ac3c007409bb0700b40ecd' 98 | '10ebf2f4ebfd2bc9e464eb002402e0f82402c3496e76616c696420706172746974696f6e207461626c65004572726f72' 99 | '206c6f6164696e67206f7065726174696e672073797374656d004d697373696e67206f7065726174696e672073797374' 100 | '656d000000637b9a14a9064200008020210007df130c000800000020030000df140c07feffff0028030000d06c0200fe' 101 | 'ffff07feffff00f86f0200f80f000000000000000000000000000000000055aa'.decode('hex'), 102 | 'suspicious_behaviour': [], 103 | 'known_code_signature': ['NT6.1+ MBR'], 104 | } 105 | with open(sampleName, 'rb') as f_mbr: 106 | objMBR = MasterBootRecord(f_mbr, os.path.getsize(f_mbr.name), whitelist=whitelist) 107 | dParsed = objMBR.getDictRecord() 108 | assert dParsed == dExpected 109 | 110 | 111 | def test_mbr_empty_with_whitelist(whitelist): 112 | sampleName = os.path.join('test_data', 'mbr_empty.bin') 113 | 114 | with pytest.raises(InvalidMBRError) as e: 115 | with open(sampleName, 'rb') as f_mbr: 116 | objMBR = MasterBootRecord(f_mbr, os.path.getsize(f_mbr.name), whitelist=whitelist) 117 | assert "Invalid MBR structure: expected " in str(e.value) 118 | 119 | 120 | def test_mbr_empty_code_with_whitelist(whitelist): 121 | sampleName = os.path.join('test_data', 'mbr_empty_code.bin') 122 | 123 | dParsed = {} 124 | dExpected = { 125 | 'record_type': 'MBR', 126 | 'sample_name': sampleName, 127 | 'partition_table': [{'Number': 1, 'Attributes': 'Active', 'Type': 'NTFS', 128 | 'Start sector': 2048, 'Size in sectors': 204800}, 129 | {'Number': 2, 'Attributes': 'Inactive', 'Type': 'NTFS', 130 | 'Start sector': 206848, 'Size in sectors': 40685568}, 131 | {'Number': 3, 'Attributes': 'Inactive', 'Type': 'NTFS', 132 | 'Start sector': 40892416, 'Size in sectors': 1046528}, 133 | ], 134 | 'disk_signature': '14a90642'.decode('hex'), 135 | 'oem_id': None, 136 | 'code_SHA256': None, 137 | 'record_raw': '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 138 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 139 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 140 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 141 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 142 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 143 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 144 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 145 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 146 | '000000000000000014a9064200008020210007df130c000800000020030000df140c07feffff0028030000d06c0200fe' 147 | 'ffff07feffff00f86f0200f80f000000000000000000000000000000000055aa'.decode('hex'), 148 | 'suspicious_behaviour': ['Code section is null'], 149 | 'known_code_signature': [], 150 | } 151 | with open(sampleName, 'rb') as f_mbr: 152 | objMBR = MasterBootRecord(f_mbr, os.path.getsize(f_mbr.name), whitelist=whitelist) 153 | dParsed = objMBR.getDictRecord() 154 | assert dParsed == dExpected 155 | 156 | 157 | def test_mbr_tc_with_whitelist(whitelist): 158 | sampleName = os.path.join('test_data', 'mbr_tc.bin') 159 | 160 | dParsed = {} 161 | dExpected = { 162 | 'record_type': 'MBR', 163 | 'sample_name': sampleName, 164 | 'partition_table': [{'Number': 1, 'Attributes': 'Active', 'Type': 'NTFS', 165 | 'Start sector': 2048, 'Size in sectors': 204800}, 166 | {'Number': 2, 'Attributes': 'Inactive', 'Type': 'NTFS', 167 | 'Start sector': 206848, 'Size in sectors': 40685568}, 168 | {'Number': 3, 'Attributes': 'Inactive', 'Type': 'NTFS', 169 | 'Start sector': 40892416, 'Size in sectors': 1046528}, 170 | ], 171 | 'disk_signature': 'c9a7ee57'.decode('hex'), 172 | 'oem_id': None, 173 | 'code_SHA256': 'e6e6605c48665800786de4651ade2893970aafb1237a06db0943a8603dd4fce1'.decode('hex'), 174 | 'record_raw': 'ea1e7c00002054727565437279707420426f6f74204c6f616465720d0a00fa33c08ed88ed0bc007cfbf606b67d017507' 175 | '8d36057ce8dc00b80090813e13045c027d0eb80088813e13043c027d03b800208ec032c0bf0001b9ff6efcf3aa8cc02d' 176 | '00088ec0b102b004bb0001e8b4006633dbbe0001b90008e8ba006653bb000db106b039f606467d017404b01ab124e891' 177 | '00665bbe000d8b0eb07de89700663b1eb27d7425f606467d01750ec606467d01b120f606b77d0275ad8d36557de85300' 178 | '8d36057ce84c00ebfe8cc08ed8fa8ed0bc0080fb52680a0d68007a6800810e68e77c06680001cb83c4065a0e1f85c074' 179 | '098d36557de81b00ebfe8a36b77d8cc00500088ec08ed8fa8ed0bcfc6ffb06680001cb33dbb40efcac84c07404cd10eb' 180 | 'f7c3b500b600b402cd1373078d36477de8e0ffc31e061f6633c0fcac6603d866d1c3e2f71fc3004469736b206572726f' 181 | '720d0a0700074c6f616465722064616d61676564212055736520526573637565204469736b3a20526570616972204f70' 182 | '74696f6e73203e20526573746f726500000000000000000000000000000000000000000000000000000000000000071a' 183 | '722e832e05b50006c9a7ee5700008020210007df130c000800000020030000df140c07feffff0028030000d06c0200fe' 184 | 'ffff07feffff00f86f0200f80f000000000000000000000000000000000055aa'.decode('hex'), 185 | 'suspicious_behaviour': [], 186 | 'known_code_signature': ['TrueCrypt MBR'], 187 | } 188 | with open(sampleName, 'rb') as f_mbr: 189 | objMBR = MasterBootRecord(f_mbr, os.path.getsize(f_mbr.name), whitelist=whitelist) 190 | dParsed = objMBR.getDictRecord() 191 | assert dParsed == dExpected 192 | 193 | def test_mbr_uefi_with_whitelist(whitelist): 194 | sampleName = os.path.join('test_data', 'mbr_protect_uefi.bin') 195 | 196 | dParsed = {} 197 | dExpected = { 198 | 'record_type': 'MBR', 199 | 'sample_name': sampleName, 200 | 'partition_table': [{'Number': 1, 'Attributes': 'Inactive', 'Type': 'PROTECTIVE_MBR', 201 | 'Start sector': 1, 'Size in sectors': 41943039}], 202 | 'disk_signature': '00000000'.decode('hex'), 203 | 'oem_id': None, 204 | 'code_SHA256': None, 205 | 'record_raw': '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 206 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 207 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 208 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 209 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 210 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 211 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 212 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 213 | '000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000' 214 | '000000000000000000000000000000000100eefeffff01000000ffff7f02000000000000000000000000000000000000' 215 | '00000000000000000000000000000000000000000000000000000000000055aa'.decode('hex'), 216 | 'suspicious_behaviour': [], 217 | 'known_code_signature': ['Protective MBR', 'UEFI (no legacy boot code)'], 218 | } 219 | with open(sampleName, 'rb') as f_mbr: 220 | objMBR = MasterBootRecord(f_mbr, os.path.getsize(f_mbr.name), whitelist=whitelist) 221 | dParsed = objMBR.getDictRecord() 222 | assert dParsed == dExpected 223 | -------------------------------------------------------------------------------- /LICENSE: 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See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | {project} Copyright (C) {year} {fullname} 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | -------------------------------------------------------------------------------- /bootcode_parser.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env python2 2 | # -*- coding:utf-8 -*- 3 | 4 | from __future__ import unicode_literals, print_function 5 | from abc import ABCMeta, abstractmethod 6 | import logging 7 | import hashlib 8 | import csv 9 | import os 10 | import capstone 11 | import capstone.x86 12 | import sys 13 | from array import array 14 | try: 15 | from construct import ConstructError, Adapter, Struct, Sequence, Array, \ 16 | Int8ul, Int8ub, Int16ul, Int32ul, Int64ul, Int8sl, Bytes, \ 17 | Enum, String, Octet, BitsInteger, BitStruct, Padding, this, Pass, Const, \ 18 | version as construct_version 19 | if construct_version[:2] != (2, 8): 20 | print('This version of {0} is compatible with Construct v2.8 only (you have v{1}.{2}).' 21 | .format(__file__, construct_version[0], construct_version[1])) 22 | sys.exit(1) 23 | except ImportError: 24 | print('This version of {0} is compatible with Construct v2.8.x only. ' 25 | 'You either don\'t have the right version of Construct or don\'t have Construct at all.' 26 | .format(__file__)) 27 | sys.exit(1) 28 | 29 | 30 | 31 | class _Utf16(Adapter): 32 | def _decode(self, obj, context): 33 | return array('B', obj[1]).tostring().decode('utf16').strip('\x00') 34 | 35 | 36 | def PascalUtf16(size_type=Int16ul): 37 | """Parse a length-defined string in UTF-16.""" 38 | 39 | return _Utf16(Sequence( 40 | size_type, 41 | Bytes(this[0] * 2), 42 | )) 43 | 44 | 45 | BOOTRECORD_WHITELIST_PATH = os.path.join(os.path.dirname(__file__), 'data', 'bootrecord_whitelist.csv') 46 | 47 | 48 | class BootRecord(object): 49 | __metaclass__ = ABCMeta 50 | 51 | def __init__(self, source, size, offset=None, whitelist=()): 52 | """ 53 | Default constructor which loads the raw data from a file. 54 | No sanity check is performed on the size or existence of the file. 55 | """ 56 | # Common to MBR, VBR and IPL 57 | self._suspiciousBehaviour = [] 58 | self._signature = [] 59 | self._codeHash = None 60 | # MBR-specific 61 | self._partTable = [] 62 | self._diskSignature = None 63 | # VBR-specific 64 | self._oemId = None 65 | 66 | self._whitelist = whitelist 67 | self._offset = offset 68 | 69 | # Input may be a file object, a list of file paths or directly the raw data (str) 70 | if isinstance(source, file): 71 | self._sample = source.name 72 | self._raw = source.read(size) 73 | elif isinstance(source, (list, tuple)): 74 | self._sample = ', '.join(source) 75 | self._raw = str() 76 | for f in source: 77 | with open(f, 'rb') as f_data: 78 | self._raw += f_data.read() 79 | elif isinstance(source, str): 80 | self._sample = None 81 | self._raw = source 82 | else: 83 | raise InvalidBootRecordError('Cannot instantiate a BootRecord object from {0}'.format(type(source))) 84 | 85 | self._logger = logging.LoggerAdapter(logging.getLogger('artefact'), 86 | {'objectid': getattr(self, '_sample', None), 'stage': self._type}) 87 | self._parse() 88 | 89 | def __eq__(self, other): 90 | return self._raw == other.getRaw() 91 | 92 | def __ne__(self, other): 93 | return self._raw != other.getRaw() 94 | 95 | @abstractmethod 96 | def _parse(self): 97 | """ 98 | Abstract private method called upon initialization to unpack the raw data into the boot record structure 99 | This method should only be called by BootRecord.__init__ 100 | It returns nothing but updates several private attributes of the object 101 | """ 102 | pass 103 | 104 | @abstractmethod 105 | def _checkCode(self, rawCode): 106 | """ 107 | Abstract private helper method that tries to find malicious behaviour in the boot code. 108 | When something is found, self._suspiciousBehaviour is updated. 109 | 110 | Args: 111 | rawCode: str of the code section 112 | 113 | Returns: nothing 114 | """ 115 | pass 116 | 117 | def _matchHash(self, codeHash, expectedLoader): 118 | """ 119 | Private method that checks if the hash of the boot record's code section is present in the whitelist. 120 | If a match is found, self._signature is updated with the content of the "Comment" column of the whitelist. 121 | This method also checks that the whitelist entry matches what was expected from previous processing steps. 122 | This method updates self._codeHash with the hash of the code section 123 | 124 | Args: 125 | hash: hashlib.hash object 126 | expectedLoader: unicode string of the kind of loader that was expected from previous processing or None 127 | 128 | Returns: nothing 129 | 130 | """ 131 | self._codeHash = codeHash.digest() 132 | # Use the hexdigest for whitelist matching 133 | hexDigest = codeHash.hexdigest() 134 | for dictWh in self._whitelist: 135 | if dictWh['Type'] == self._type and dictWh['SHA256'] == hexDigest: 136 | self._signature.append(dictWh['Comment']) 137 | # In addition to signature matching, also check that the loader is what we expected 138 | if expectedLoader and expectedLoader != dictWh['Comment']: 139 | self._suspiciousBehaviour.append('{0} earlier detection expected "{1}" but signature matched "{2}"' 140 | .format(self._type, expectedLoader, dictWh['Comment'])) 141 | 142 | def getDictRecord(self): 143 | """ 144 | Public method to retrieve a dict of the interesting values of the BootRecord 145 | 146 | Returns: dict 147 | 148 | """ 149 | record = { 150 | 'record_type': self._type, 151 | 'sample_name': self._sample, 152 | 'partition_table': self._partTable, 153 | 'disk_signature': self._diskSignature, 154 | 'oem_id': self._oemId, 155 | 'code_SHA256': self._codeHash, 156 | 'record_raw': self._raw, 157 | 'suspicious_behaviour': self._suspiciousBehaviour, 158 | 'known_code_signature': self._signature, 159 | } 160 | return record 161 | 162 | def getRaw(self): 163 | return self._raw 164 | 165 | 166 | class MasterBootRecord(BootRecord): 167 | _MBR_STRUCT = Struct( 168 | 'bootloader_code' / Bytes(440), 169 | 'disk_signature' / Bytes(4), 170 | Padding(2), 171 | 'partitions' / Array( 172 | 4, 173 | Struct( 174 | 'state' / Int8sl, 175 | 'beginning' / BitStruct( 176 | 'head' / Octet, 177 | 'sect' / BitsInteger(6), 178 | 'cyl' / BitsInteger(10), 179 | ), 180 | Enum('type' / Int8ub, 181 | Nothing=0x00, 182 | FAT12=0x01, 183 | XENIX_ROOT=0x02, 184 | XENIX_USR=0x03, 185 | FAT16_old=0x04, 186 | Extended_DOS=0x05, 187 | FAT16=0x06, 188 | FAT32=0x0b, 189 | FAT32_LBA=0x0c, 190 | NTFS=0x07, 191 | LINUX_SWAP=0x82, 192 | LINUX_NATIVE=0x83, 193 | PROTECTIVE_MBR=0xee, 194 | _default_=Pass, 195 | ), 196 | 'ending' / BitStruct( 197 | 'head' / Octet, 198 | 'sect' / BitsInteger(6), 199 | 'cyl' / BitsInteger(10), 200 | ), 201 | 'sector_offset' / Int32ul, # offset from MBR in sectors 202 | 'size' / Int32ul, # in sectors 203 | ) 204 | ), 205 | Const('55aa'.decode('hex')), 206 | ) 207 | 208 | def __init__(self, filePath, size, offset=None, whitelist=()): 209 | self._type = 'MBR' 210 | super(MasterBootRecord, self).__init__(filePath, size, offset, whitelist) 211 | 212 | def _parse(self): 213 | """ 214 | Main method in charge of parsing the MBR. 215 | It will try to parse the boot record according to documented known structure and extract the partition table 216 | disk signature and code section. 217 | It will then try to narrow down invariant code, hash it and match the hash against a whitelist. 218 | If no match was found, it will try some simple heuristics to detect malicious behaviours. 219 | 220 | Returns: nothing 221 | 222 | """ 223 | try: 224 | mbr = self._MBR_STRUCT.parse(self._raw) 225 | except ConstructError as e: 226 | raise InvalidMBRError('Invalid MBR structure: {0}\n{1}'.format(e, hexdump(self._raw))) 227 | 228 | self._parsePartTable(mbr.partitions) 229 | 230 | # Windows stores the disk signature at 0x1B8, other MBRs seem to leave this area alone 231 | self._diskSignature = mbr.disk_signature 232 | 233 | # If code section is null, check for protective MBR signature (detected in partition table parsing). If found, 234 | # then the machine is likely using UEFI instead of BIOS to boot. If not, it could mean that the sample being 235 | # analyzed has been tampered by a bootkit 236 | if mbr.bootloader_code.encode('hex') == 440 * '00': 237 | if 'Protective MBR' in self._signature: 238 | self._signature.append('UEFI (no legacy boot code)') 239 | else: 240 | self._suspiciousBehaviour.append('Code section is null') 241 | else: 242 | expectedLoader, invariantCode = self._getInvariantCode(mbr.bootloader_code) 243 | codeHash = hashlib.sha256(invariantCode) 244 | self._matchHash(codeHash, expectedLoader) 245 | if len(self._signature) == 0: 246 | # No whitelisted signature matched, try some simple heuristics to flag this MBR as malicious 247 | # Note that the self._checkCode method is only given the "invariant" code section to help with the 248 | # disassembling. This will obviously leads to broken offsets, but it doesn't matter since the heuristics 249 | # don't use them. 250 | self._checkCode(invariantCode) 251 | 252 | def _parsePartTable(self, partitions): 253 | """ 254 | Private method that parses the partition table of the MBR. Updates self._partTable list. 255 | 256 | Args: 257 | partitions: Construct.Container object of the partition table 258 | 259 | Returns: nothing 260 | """ 261 | partNum = 0 262 | for part in partitions: 263 | partNum += 1 264 | # Assume a partition entry without size (in LBA) or type is invalid, and do not include it in the listing. 265 | if part.size != 0 and part.type != 'Nothing': 266 | dPart = { 267 | 'Number': partNum, 268 | 'Attributes': 'Active' if part.state < 0 else 'Inactive', 269 | 'Type': part.type, 270 | 'Start sector': part.sector_offset, 271 | 'Size in sectors': part.size 272 | } 273 | self._partTable.append(dPart) 274 | else: 275 | self._logger.debug('Ignoring invalid partition: %s', repr(part)) 276 | # Protective MBR is just informative, keep on parsing partition table in case there is a valid 277 | # active partition 278 | if part.type == 'PROTECTIVE_MBR' and partNum == 1: 279 | self._logger.debug('Protective MBR detected, MBR partition table should not be taken into account. ' 280 | 'Look for the GPT table partition instead') 281 | self._signature.append('Protective MBR') 282 | 283 | def _getInvariantCode(self, rawCode): 284 | """ 285 | Helper method that tries to narrow down "invariant code" which can be hashed and compared to well known 286 | signatures. Most MBRs have localized error strings which must be excluded from the hash computation because 287 | they may vary from a country to another. 288 | First, this method tries to detect what kind of MBR it is dealing with. Most of the time, it is enough to 289 | to look for some known hardcoded strings that identify "well known" MBR (such as Truecrypt, GRUB2, etc...). 290 | Then, this method finds where the strings are and "removes" them (as in "does not include them"). 291 | Finding these strings can be achieved by quickly studying the assembly code and looking for how these 292 | strings are echoed on screen at boot time (using interrupt 0x10). 293 | This research only needs to be done once for each type of MBR but requires an analyst to do it by static 294 | analysis. This script cannot take care of this. This method merely implements the results of such work. 295 | 296 | Currently supported MBR are: 297 | - Truecrypt 298 | - McAfee Endpoint Encryption (Safeboot) 299 | - GRUB2 300 | - Windows (XP to 10) 301 | 302 | Args: 303 | rawCode: str of the code section 304 | 305 | Returns: 2-tuple (unicode string of expected loader, concatenated strings of invariant sections of code) 306 | 307 | """ 308 | # By default, assume all the MBR code section will be hashed. It is obviously wrong in most cases, but it allows 309 | # for a "default case" which will automatically matches no known hash in case something goes wrong with the 310 | # detection. 311 | codeStart = 0 312 | codeEnd = len(rawCode) 313 | expectedLoader = None 314 | invariantCode = str() 315 | 316 | # TrueCrypt (detected with the hardcoded string following the first jump: " TrueCrypt Boot Loader") 317 | if rawCode[0x5:0x1b].encode('hex').upper() == '2054727565437279707420426F6F74204C6F61646572': 318 | # TrueCrypt uses hardcoded and not-localized error strings. Therefore every TrueCrypt MBR should have the 319 | # same code from start to end 320 | expectedLoader = 'TrueCrypt MBR' 321 | 322 | # MacAfee SafeBoot (detected with the hardcoded string following the first jump: "Safeboot ") 323 | elif rawCode[0x3:0xc].encode('hex').upper() == '53616665426F6F7420': 324 | # Two versions have been seen but both start with a jump to the same offset (0x26). 325 | # There are some strings at the of the code section but localization is unlikely so it will be assumed 326 | # to be hardcoded (until a localized version is found...). 327 | # Therefore, Safeboot code can be hashed from 0x26 to the end of code section 328 | invariantCode += rawCode[:0x3] # Hash the first JMP 329 | codeStart = 0x26 330 | expectedLoader = 'Safeboot MBR' 331 | 332 | # GRUB (detected with the hardcoded string "GRUB " located at 0x188) 333 | elif rawCode[0x188:0x18d].encode('hex').upper() == '4752554220': 334 | # GRUB has some error strings but they are hardcoded and not localized so they can be included in the hash 335 | # computation. However GRUB can be installed on a disk (MBR) as well as on a partition (in a kind of VBR). 336 | # But in both cases the code used is the same. Since a BPB is needed for the latter case it is also present 337 | # in the MBR (but not needed). It therefore has to be excluded from the hash computation. 338 | # GRUB is jumping over the BIOS Parameter Block located between 0x3 and 0x5a. 339 | # It should be followed by the kernel address (word), kernel sector (dword), kernel sector high (dword) and 340 | # boot drive (byte). Therefore the code really starts at 0x65. 341 | # These values are hardcoded in boot.img and have little chance to change anytime soon. 342 | codeStart = 0x65 343 | invariantCode += rawCode[:0x3] # Hash the first JMP 344 | expectedLoader = 'GRUB2 MBR' 345 | 346 | # Windows MBR cannot be detected with hardcoded strings, so they fall in the default case and further checks 347 | # are then made based on the hypothesis that this is indeed a Windows MBR. 348 | else: 349 | # Starting with NT5.0, the MBR contains localized strings which must be excluded from the hash computation. 350 | # These strings are located after the code, at 3 different offsets which can be calculated by adding 0x100 351 | # to the values respectively stored in bytes 0x1b5, 0x1b6 and 0x1b7 (last bytes of the code section). 352 | # Eg: The first localized string is at : 0x100 + the value saved at offset 0x1B5 353 | # Even though localized strings can be of different lengths, the offset of the first one does not vary 354 | # given one Windows version. This can therefore be used to tell Windows versions apart. 355 | firstStrOffset = Int8ub.parse(rawCode[0x1b5]) 356 | # Windows NT5 357 | if firstStrOffset == 0x2c: 358 | expectedLoader = 'NT5.1/NT5.2 MBR' 359 | codeEnd = 0x100 + firstStrOffset 360 | # Windows NT6.0 361 | elif firstStrOffset == 0x62: 362 | expectedLoader = 'NT6.0 MBR' 363 | codeEnd = 0x100 + firstStrOffset 364 | # Windows NT6.1+ 365 | elif firstStrOffset == 0x63: 366 | expectedLoader = 'NT6.1+ MBR' 367 | codeEnd = 0x100 + firstStrOffset 368 | else: 369 | self._suspiciousBehaviour.append('Invalid string offset: {0:#x}'.format(firstStrOffset)) 370 | self._logger.debug('First localized string offset is wrong for a windows MBR.' 371 | 'It should be 0x2c, 0x62 or 0x63) : {0:#x}'.format(firstStrOffset)) 372 | 373 | self._logger.debug('Expecting {0}. Code starts at {1:#x} and ends at {2:#x}' 374 | .format(expectedLoader, codeStart, codeEnd)) 375 | 376 | invariantCode += rawCode[codeStart:codeEnd] 377 | return expectedLoader, invariantCode 378 | 379 | def _checkCode(self, rawCode): 380 | md = capstone.Cs(capstone.CS_ARCH_X86, capstone.CS_MODE_16) 381 | md.detail = True 382 | 383 | checkJmp = True 384 | for i in md.disasm(rawCode, 0): 385 | # Check for JUMPs and CALLs before the first PUSH/RET. 386 | if checkJmp and len(i.groups) > 0: 387 | # Group check if available 388 | if hasattr(capstone.x86, 'X86_GRP_CALL') and hasattr(capstone.x86, 'X86_GRP_RET'): 389 | if capstone.x86.X86_GRP_CALL in i.groups or capstone.x86.X86_GRP_JUMP in i.groups: 390 | self._suspiciousBehaviour.append('JMP or CALL before relocation') 391 | checkJmp = False 392 | elif capstone.x86.X86_GRP_RET in i.groups: 393 | # Stop search after the first PUSH/RET 394 | checkJmp = False 395 | # Manual check in case capstone version doesn't support CALL and RET groups 396 | else: 397 | if i.mnemonic[0] == 'j' or i.mnemonic == 'call': 398 | self._suspiciousBehaviour.append('JMP or CALL before relocation') 399 | checkJmp = False 400 | elif i.mnemonic[:3] == 'ret': 401 | # Stop search after the first PUSH/RET 402 | checkJmp = False 403 | 404 | # Check for unknown interrupt 405 | if i.mnemonic == 'int' and i.bytes[1] not in (0x10, 0x13, 0x18, 0x1a): 406 | self._suspiciousBehaviour.append('Unknown Interrupt : {0:#x}'.format(i.bytes[1])) 407 | 408 | 409 | class VolumeBootRecord(BootRecord): 410 | _NTFS_VBR_STRUCT = Struct( 411 | 'JumpOverBPB' / Bytes(3), 412 | 'OemId' / String( 8), 413 | 'BiosParameterBlock' / Struct( 414 | 'SectorSize' / Int16ul, 415 | 'SectorsPerCluster' / Int8ul, 416 | 'Reserved1' / Bytes(2), 417 | 'MustBeZero1' / Bytes(3), 418 | 'MustBeZero2' / Bytes(2), 419 | 'MediaDescriptor' / Int8ul, 420 | 'MustBeZero3' / Bytes(2), 421 | 'SectorsPerTrack' / Int16ul, 422 | 'NumberOfHeads' / Int16ul, 423 | 'HiddenSectors' / Int32ul, 424 | 'NotUsed1' / Bytes(4), 425 | 'DriveNumber' / Const('80'.decode('hex')), 426 | 'Reserved2' / Bytes(3), 427 | 'TotalSectors' / Int64ul, 428 | 'MFTCluster' / Int64ul, 429 | 'MFTMirrCluster' / Int64ul, 430 | 'ClustersPerMFTRecord' / Int8sl, 431 | 'NotUsed2' / Bytes(3), 432 | 'ClustersPerIdxBuffer' / Int8sl, 433 | 'NotUsed3' / Bytes(3), 434 | 'VolumneSN' / Int64ul, 435 | 'NotUsed4' / Bytes(4), 436 | ), 437 | 'Code' / Bytes( 426), 438 | Const('55aa'.decode('hex')), 439 | ) 440 | 441 | _BITLOCKER_VBR_STRUCT = Struct( 442 | 'JumpOverBPB' / Bytes(3), 443 | 'OemId' / Const('-FVE-FS-'.encode('utf8')), 444 | 'BiosParameterBlock' / Struct( 445 | 'SectorSize' / Int16ul, 446 | 'SectorsPerCluster' / Int8ul, 447 | 'Reserved1' / Bytes(2), 448 | 'MustBeZero1' / Bytes(3), 449 | 'MustBeZero2' / Bytes(2), 450 | 'MediaDescriptor' / Int8ul, 451 | 'MustBeZero3' / Bytes(2), 452 | 'SectorsPerTrack' / Int16ul, 453 | 'NumberOfHeads' / Int16ul, 454 | 'HiddenSectors' / Int32ul, 455 | 'TotalSectors' / Int32ul, 456 | 'SectorsPerFAT' / Int32ul, 457 | 'FATFlags' / Int16ul, 458 | 'Version' / Int16ul, 459 | 'RootDirCluster' / Int32ul, 460 | 'FSInfoSector' / Int16ul, 461 | 'BackupSector' / Int16ul, 462 | 'Reserved2' / Bytes(12), 463 | 'DriveNumber' / Const('80'.decode('hex')), 464 | 'Reserved3' / Bytes(1), 465 | 'ExtendedBootSignature' / Bytes(1), 466 | 'VolumneSN' / Int32ul, 467 | 'VolumeLabel' / Const('NO NAME '.encode('utf8')), 468 | 'SystemId' / Const('FAT32 '.encode('utf8')), 469 | ), 470 | 'Code1' / Bytes(70), 471 | 'BitlockerGUID' / Bytes(16), 472 | 'FVEMetadataBlockOffset1' / Int64ul, 473 | 'FVEMetadataBlockOffset2' / Int64ul, 474 | 'FVEMetadataBlockOffset3' / Int64ul, 475 | 'Code2' / Bytes(307), 476 | 'FirstStrOffset' / Int8ul, 477 | 'SecondStrOffset' / Int8ul, 478 | 'ThirdStrOffset' / Int8ul, 479 | Const('55aa'.decode('hex')), 480 | ) 481 | 482 | def __init__(self, filePath, size, offset=None, whitelist=()): 483 | self._type = 'VBR' 484 | super(VolumeBootRecord, self).__init__(filePath, size, offset, whitelist) 485 | 486 | def _parse(self): 487 | """ 488 | Main method in charge of parsing the VBR. 489 | It will try to parse the boot record according to known structures (NTFS and Bitlocker supported). 490 | It will then try to narrow down invariant code, hash it and match the hash against a whitelist. 491 | If no match was found, it will try some simple heuristics to detect malicious behaviours. 492 | Finally it will compare the HiddenSectors value in BPB to that of the record's dump offset. 493 | 494 | Returns: nothing 495 | 496 | """ 497 | try: 498 | # This will parse both NTFS and Vista bitlocker volumes since they only differ by their OEM ID 499 | vbr = self._NTFS_VBR_STRUCT.parse(self._raw) 500 | expectedLoader, invariantCode = self._getInvariantCode('NTFS', vbr) 501 | except ConstructError as e1: 502 | # Retry with Bitlocker (Win7+) volume header structure 503 | try: 504 | vbr = self._BITLOCKER_VBR_STRUCT.parse(self._raw) 505 | expectedLoader, invariantCode = self._getInvariantCode('bitlocker', vbr) 506 | except ConstructError as e2: 507 | raise InvalidVBRError('Invalid VBR structure: e1={0}, e2={1}\n{2}'.format(e1, e2, hexdump(self._raw))) 508 | 509 | self._oemId = vbr.OemId 510 | self._bpb = vbr.BiosParameterBlock 511 | codeHash = hashlib.sha256(invariantCode) 512 | self._matchHash(codeHash, expectedLoader) 513 | 514 | # If no whitelisted signature matched, try some simple heuristics to flag this VBR as malicious 515 | # Note that the self._checkCode method is only given the "invariant" code section to help with the 516 | # disassembling. This will obviously leads to broken offsets, but it doesn't matter since the heuristics don't 517 | # use them. 518 | if len(self._signature) == 0: 519 | self._checkCode(invariantCode) 520 | 521 | # At last, compare the offset at which this VBR was found with the value of the BPB HiddenSectors 522 | if self._offset is not None \ 523 | and (vbr.BiosParameterBlock.HiddenSectors * vbr.BiosParameterBlock.SectorSize) != self._offset: 524 | self._suspiciousBehaviour.append( 525 | 'Suspicious HiddenSectors value: {0} ({1} bytes)' 526 | .format(vbr.BiosParameterBlock.HiddenSectors, 527 | vbr.BiosParameterBlock.HiddenSectors * vbr.BiosParameterBlock.SectorSize)) 528 | 529 | def _getInvariantCode(self, vbrType, vbrStruct): 530 | """ 531 | Helper method that finds all the sections of the boot code that can be hashed and compared to a whitelist. 532 | This means that localized strings and other variable parameters (BPB, etc...) are excluded. 533 | Currently, this method only supports NTFS and Bitlocker VBR. 534 | 535 | Args: 536 | vbrType: unicode string corresponding to the VBR type ('NTFS' or 'bitlocker') 537 | vbrStruct: construct.container of the VBR 538 | 539 | Returns: 2-tuple (unicode string of expected loader, concatenated strings of invariant sections of code) 540 | 541 | """ 542 | codeStart = 0 543 | codeEnd = None 544 | invariantCode = str() 545 | expectedLoader = None 546 | 547 | if vbrType == 'NTFS': 548 | # The first three bytes are a jump over the NTFS BPB to where the code really starts (0x54) and a NOP 549 | invariantCode += vbrStruct.JumpOverBPB 550 | codeStart = 0x54 551 | # NTFS VBR contains localized strings which must be excluded from the hash computation. 552 | # Before Windows 8, these strings are located at 4 different offsets which can be calculated by adding 553 | # 0x100 to the values respectively stored in bytes 0x1f8, 0x1f9, 0x1fa and 0x1fb. 554 | # Starting from Windows 8, these strings are located at 3 different offsets which are directly stored in 555 | # little endian words respectively at 0x1f6, 0x1f8 and 0x1fa 556 | # Since there is no easy way to tell which version of Windows we are dealing with beforehand, we first 557 | # assume it is a Windows < 8 by testing 0x1f8 against all the known first offset. If all tests fail, assume 558 | # it is Windows >= 8 and check 0x1f6 against the only known first offset (to date) 559 | firstStrOffset = Int8ub.parse(self._raw[0x1f8]) 560 | # Windows NT5 561 | if firstStrOffset == 0x83: 562 | expectedLoader = 'NT5.1/NT5.2 VBR' 563 | codeEnd = 0x100 + firstStrOffset 564 | # Windows NT6.0 565 | elif firstStrOffset == 0x80: 566 | expectedLoader = 'NT6.0 VBR' 567 | codeEnd = 0x100 + firstStrOffset 568 | # Windows NT6.1 569 | elif firstStrOffset == 0x8c: 570 | expectedLoader = 'NT6.1 VBR' 571 | codeEnd = 0x100 + firstStrOffset 572 | # Windows NT6.2+ 573 | else: 574 | firstStrOffset = Int16ul.parse(self._raw[0x1f6:0x1f8]) 575 | if firstStrOffset == 0x18a: 576 | expectedLoader = 'NT6.2+ VBR' 577 | codeEnd = firstStrOffset 578 | 579 | if codeEnd is None: 580 | self._suspiciousBehaviour.append('Invalid string offset: {0:#x}'.format(firstStrOffset)) 581 | self._logger.debug('First localized string offset is wrong for a NTFS VBR: {0:#x}. ' 582 | 'It should be 0x83, 0x80, 0x8c or 0x18a.'.format(firstStrOffset)) 583 | codeEnd = 0 584 | 585 | elif vbrType == 'bitlocker': 586 | expectedLoader = 'NT6.1+ Bitlocker VBR' 587 | # The first three bytes are a jump over the NTFS BPB to where the code really starts (0x5A) and a NOP 588 | invariantCode += vbrStruct.JumpOverBPB 589 | # First section of code (_BITLOCKER_VBR_STRUCT.Code1) 590 | invariantCode += vbrStruct.Code1 591 | # In the second section of code, there are localized strings which must be excluded from hash computation. 592 | # Their offsets are stored in the last 3 bytes before the VBR signature (0x55aa). 593 | # For Windows 8, 8.1 and 10, the first string offset seems to always be 0x100 (ie. FirstStrOffset = 0x00) 594 | if vbrStruct.FirstStrOffset != 0: 595 | self._suspiciousBehaviour.append('Invalid string offset: {0:#x}'.format(vbrStruct.FirstStrOffset)) 596 | self._logger.debug('First localized string offset is wrong for a Bitlocker VBR. ' 597 | 'It should be 0x00) : {0:#x}'.format(vbrStruct.FirstStrOffset)) 598 | codeStart = 0xc8 # Offset of Code2 599 | codeEnd = 0x100 + vbrStruct.FirstStrOffset 600 | else: 601 | raise NotImplementedError('VBR type "{0}" is not implemented yet'.format(vbrType)) 602 | 603 | self._logger.debug('Expecting {0}. Code starts at {1:#x} and ends at {2:#x}' 604 | .format(expectedLoader, codeStart, codeEnd)) 605 | 606 | invariantCode += self._raw[codeStart:codeEnd] 607 | return expectedLoader, invariantCode 608 | 609 | def _checkCode(self, code): 610 | md = capstone.Cs(capstone.CS_ARCH_X86, capstone.CS_MODE_16) 611 | md.detail = True 612 | for i in md.disasm(code, 0): 613 | # Check for unknown interrupt 614 | if i.mnemonic == 'int' and i.bytes[1] not in (0x10, 0x13, 0x18, 0x1a): 615 | self._suspiciousBehaviour.append('Unknown Interrupt : {0:#x}'.format(i.bytes[1])) 616 | 617 | 618 | class InitialProgramLoader(BootRecord): 619 | 620 | def __init__(self, filePath, size, offset=None, whitelist=()): 621 | self._type = 'IPL' 622 | super(InitialProgramLoader, self).__init__(filePath, size, offset, whitelist) 623 | 624 | def _parse(self): 625 | try: 626 | header = PascalUtf16(Int16ul).parse(self._raw) 627 | except (ConstructError, UnicodeDecodeError) as e: 628 | raise InvalidIPLError('Invalid IPL structure: {0}\n{1}'.format(e, hexdump(self._raw[:0x200]))) 629 | 630 | try: 631 | # IPL's code section is usually contained is the first 9 sectors. The remaining sectors are filled with 632 | # padding but it appears that the last (15th) sector can sometimes hold data not related to the boot process 633 | # and we need to exclude that from hash calculation. 634 | invariantCode = self._raw[:14*512] 635 | except IndexError: 636 | raise InvalidIPLError('Invalid sample size for IPL: {0} (should be 15 * 512-bytes sectors)' 637 | .format(len(self._raw))) 638 | 639 | expectedLoader = None 640 | 641 | # Starting with NT 6.2, IPL has a localized string that must be excluded from hash computation. 642 | # The difference between these two kinds of IPL can be told from the instruction located at 0x56 : 643 | # a Jump Short (EB) in case of IPL<6.2 or a Jump Near (E9) otherwise 644 | if header == 'BOOTMGR' and self._raw[0x56].encode('hex').upper() == 'E9': 645 | # The offset of the localized string seems to be stored in a DWORD at 0x117 (just before the beginning 646 | # of the assembly code). But the value seems to be an offset relative to the start of the whole 647 | # boot record (including the VBR) and not just the IPL. 648 | # Therefore we need to substract 0x200 to get the offset inside the IPL. 649 | strOffset = Int16ul.parse(self._raw[0x117:]) - 0x200 650 | # Exclude from hash calculation everything between the string offset and the beginning of code 651 | invariantCode = invariantCode[:strOffset] + invariantCode[0x119:] 652 | expectedLoader = 'NT6.2+ IPL' 653 | 654 | codeHash = hashlib.sha256(invariantCode) 655 | self._matchHash(codeHash, expectedLoader) 656 | 657 | # If no whitelisted signature matched, try some simple heuristics to flag this IPL as malicious 658 | # Note that the self._checkCode method is only given the "stripped" code section to help the disassembling. 659 | # This will obviously leads to broken offsets, but it doesn't matter since the heuristics don't use them. 660 | if len(self._signature) == 0: 661 | self._checkCode(invariantCode) 662 | 663 | def _checkCode(self, code): 664 | md = capstone.Cs(capstone.CS_ARCH_X86, capstone.CS_MODE_16) 665 | md.detail = True 666 | for i in md.disasm(code, 0): 667 | # Check for unknown interrupt 668 | if i.mnemonic == 'int' and i.bytes[1] not in (0x10, 0x13, 0x18, 0x1a): 669 | self._suspiciousBehaviour.append('Unknown Interrupt : {0:#x}'.format(i.bytes[1])) 670 | 671 | 672 | class InvalidBootRecordError(Exception): 673 | pass 674 | 675 | 676 | class InvalidMBRError(InvalidBootRecordError): 677 | pass 678 | 679 | 680 | class InvalidVBRError(InvalidBootRecordError): 681 | pass 682 | 683 | 684 | class InvalidIPLError(InvalidBootRecordError): 685 | pass 686 | 687 | 688 | def hexdump(src, length=16, sep='.'): 689 | """ 690 | @brief Return {src} in hex dump. 691 | @param[in] length {Int} Nb Bytes by row. 692 | @param[in] sep {Char} For the text part, {sep} will be used for non ASCII char. 693 | @return {Str} The hexdump 694 | 695 | @note Code borrowed from https://gist.github.com/ImmortalPC/c340564823f283fe530b 696 | """ 697 | result = [] 698 | 699 | # Python3 support 700 | try: 701 | xrange(0, 1) 702 | except NameError: 703 | xrange = range 704 | 705 | for i in xrange(0, len(src), length): 706 | subSrc = src[i:i + length] 707 | hexa = '' 708 | isMiddle = False 709 | for h in xrange(0, len(subSrc)): 710 | if h == length / 2: 711 | hexa += ' ' 712 | h = subSrc[h] 713 | if not isinstance(h, int): 714 | h = ord(h) 715 | h = hex(h).replace('0x', '') 716 | if len(h) == 1: 717 | h = '0' + h 718 | hexa += h + ' ' 719 | hexa = hexa.strip(' ') 720 | text = '' 721 | for c in subSrc: 722 | if not isinstance(c, int): 723 | c = ord(c) 724 | if 0x20 <= c < 0x7F: 725 | text += chr(c) 726 | else: 727 | text += sep 728 | result.append(('%08X: %-' + str(length * (2 + 1) + 1) + 's |%s|') % (i, hexa, text)) 729 | 730 | return '\n'.join(result) 731 | 732 | 733 | def initWhitelist(fWhitelist): 734 | whitelist = [] 735 | # CSV file content should be "Type,SHA256,Comment" 736 | with open(fWhitelist, 'rb') as fd: 737 | reader = csv.DictReader(fd) 738 | for row in reader: 739 | whitelist.append(row) 740 | return whitelist 741 | 742 | 743 | def checkResult(objBr, brType): 744 | """ 745 | Simple function to check if anything is suspicious in the BootRecord 746 | 747 | :param objBr: BootRecord object 748 | :param brType: unicode string, type of BootRecord (MBR, VBR or IPL) 749 | :return: boolean, True if everything is OK, False otherwise 750 | """ 751 | logger.extra.update({'stage': brType}) 752 | ret = True 753 | if getattr(objBr, '_signature', None): 754 | logger.info('Known signatures found: %r', getattr(objBr, '_signature')) 755 | else: 756 | ret = False 757 | logger.warning('No known code signature were found, this is highly suspicious.') 758 | if getattr(objBr, '_codeHash'): 759 | logger.debug('Sample\'s code hash is: %r', getattr(objBr, '_codeHash').encode('hex')) 760 | if getattr(objBr, '_suspiciousBehaviour'): 761 | ret = False 762 | logger.warning('Suspicious behaviours were detected: %r', getattr(objBr, '_suspiciousBehaviour')) 763 | return ret 764 | 765 | 766 | def parseBootRecord(brType, input, offset, whitelist): 767 | logger.extra.update({'stage': brType}) 768 | try: 769 | if brType == 'MBR': 770 | objBr = MasterBootRecord(input, 512, whitelist=whitelist) 771 | elif brType == 'VBR': 772 | objBr = VolumeBootRecord(input, 512, offset=offset, whitelist=whitelist) 773 | elif brType == 'IPL': 774 | objBr = InitialProgramLoader(input, 15 * 512, whitelist=whitelist) 775 | else: 776 | return 777 | checkResult(objBr, brType) 778 | except InvalidBootRecordError as e: 779 | logger.error(e) 780 | return 781 | 782 | 783 | def parseImageFile(input, sectorSize, whitelist): 784 | try: 785 | objMBR = MasterBootRecord(input, sectorSize, 0, whitelist) 786 | checkResult(objMBR, 'MBR') 787 | activePart = {} 788 | for part in getattr(objMBR, '_partTable'): 789 | # A partition is a dict with the following keys: (Number, Attributes, Type, Start sector, Size in sectors, 790 | # Name) 791 | if 'Active' in part['Attributes']: 792 | activePart = part 793 | # The first active partition is the one the MBR will load the VBR from 794 | break 795 | logger.extra.update({'stage': 'IMG'}) 796 | if activePart: 797 | logger.debug('Found active partition n°%d starting at sector %d', 798 | activePart['Number'], activePart['Start sector']) 799 | offset = activePart['Start sector'] * sectorSize 800 | input.seek(offset) 801 | objVBR = VolumeBootRecord(input, sectorSize, offset=offset, whitelist=whitelist) 802 | if not checkResult(objVBR, 'VBR'): 803 | logger.warning('VBR of the active partition located at sector %d (offset %d) is suspicious (see ' 804 | 'previous warning). This could mean that the partition table in the MBR or the BPB in ' 805 | 'the VBR has been tampered with !', activePart['Start sector'], offset) 806 | hiddenSectors = getattr(objVBR, '_bpb').HiddenSectors 807 | logger.extra.update({'stage': 'IMG'}) 808 | logger.debug('Found HiddenSectors value: %d', hiddenSectors) 809 | if hiddenSectors != (offset / sectorSize): 810 | logger.warning('HiddenSectors value in BiosParameterBlock is different than actual offset in partition ' 811 | 'table ! HiddenSectors=%d, partition table offset=%d', hiddenSectors, offset/sectorSize) 812 | # IPL is just next to the VBR. Even when sectors are 4KB in size, the VBR and IPL will be contiguous : there 813 | # is no "slack space" between the VBR and IPL. Therefore, IPL will always be located at VBR offset + 512 814 | input.seek((hiddenSectors * sectorSize) + 512) 815 | objIPL = InitialProgramLoader(input, 15 * sectorSize, whitelist=whitelist) 816 | checkResult(objIPL, 'IPL') 817 | else: 818 | logger.warning('No active partition detected in MBR !') 819 | except InvalidBootRecordError as e: 820 | logger.error(e) 821 | 822 | 823 | if __name__ == '__main__': 824 | import argparse 825 | global logger 826 | 827 | parser = argparse.ArgumentParser(description='Check boot records for known good signatures', 828 | formatter_class=argparse.RawTextHelpFormatter, 829 | add_help=True) 830 | parser.add_argument('--type', choices=['VBR', 'MBR', 'IPL', 'IMG'], required=True, 831 | type=lambda x: x.decode(sys.getfilesystemencoding()).upper(), 832 | help='Type of boot record: MBR, VBR or IPL. Or whole disk image.') 833 | parser.add_argument('--input', required=True, type=lambda x: x.decode(sys.getfilesystemencoding()), nargs='+', 834 | help='Input file(s) to check') 835 | parser.add_argument('--offset', type=int, 836 | help='Offset in bytes at which the boot record was dumped. Required only for VBR. Without it, ' 837 | 'some heuristics to detect malicious VBR will not work.') 838 | # Note that when using native 4K disks, Windows can only be installed in UEFI. Support for 4K sectors in this script 839 | # is mostly for testing purpose since no "default" Windows installation can ever be found on native 4K disks. 840 | # However, this option can be used to test a non-booting native 4K disk/volume. 841 | parser.add_argument('--sector-size', type=int, default=512, 842 | help='Disk sector size in bytes. Only applies for disk image input. Defaults to 512.') 843 | parser.add_argument('--whitelist', help='CSV file containing whitelisted boot record signatures. ' 844 | 'Without it, the boot record will always be flagged as suspicious. ' 845 | 'Defaults to {0}'.format(BOOTRECORD_WHITELIST_PATH), 846 | default=BOOTRECORD_WHITELIST_PATH, type=lambda x: x.decode(sys.getfilesystemencoding())) 847 | parser.add_argument('--logLevel', default='INFO', choices=['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'], 848 | help='Show debug messages according to the level provided.') 849 | args = parser.parse_args() 850 | 851 | logging.basicConfig(level=getattr(logging, args.logLevel.upper()), 852 | format='%(levelname)-8s - [%(objectid)s] [%(stage)s] %(message)s') 853 | logger = logging.LoggerAdapter(logging.getLogger(__file__), {'objectid': None, 'stage': 'main'}) 854 | 855 | if args.type == 'VBR' and args.offset is None: 856 | logger.error('--offset is required when parsing VBR') 857 | sys.exit(1) 858 | 859 | if args.whitelist is not None: 860 | whitelist = initWhitelist(args.whitelist) 861 | else: 862 | whitelist = [] 863 | 864 | for inputFile in args.input: 865 | logger.extra.update({'objectid': inputFile}) 866 | with open(inputFile, 'rb') as f_input: 867 | if args.type == 'IMG': 868 | logger.debug('Parsing disk image file %s with %d whitelisted records', args.input, len(whitelist)) 869 | parseImageFile(f_input, args.sector_size, whitelist) 870 | else: 871 | logger.debug('%s dumped %swith %d whitelisted records', args.type, 872 | 'at offset {0} '.format(args.offset) if args.offset else '', 873 | len(whitelist)) 874 | parseBootRecord(args.type, f_input, args.offset, whitelist) 875 | 876 | # This is only useful for pytest 877 | logger = logging.LoggerAdapter(logging.getLogger(__file__), {'objectid': None, 'stage': 'main'}) 878 | --------------------------------------------------------------------------------