Files
Mobile-Security-Framework-M…/mobsf/StaticAnalyzer/views/common/shared_func.py
T
Ajin Abraham 5ce7e237af [4.2.8] Multiple APK Analysis improvements, general Code QA & bug fixes (#2470)
* Dockerfile QA
* Add sdk-build-tools to Docker image
* Replace biplist with plistlib std lib
* Fixed a bug in iOS pbxproj parsing
* Added support for APK parsing with aapt2/aapt
* Use aapt/aapt2 as a fallback for APK parsing, files listing and string extraction
* Added "started at" to Scan task queue model #2463
* Tasks List API to return string status #2464
* Replaced all minidom calls with defusedxml.minidom
* Code QA on android manifest data extraction and parsing
* Improved android file analysis
* Improved android manifest data extraction
* Improved android icon file extraction
* Improved android app name extraction
* Improved android appstore package details extraction
* Android string extraction to fallback on aapt2 strings
* APK analysis arguments refactor
* Handle packed APKs, refactor unzip to handle malformed APK files
* Handle reserved filename conflict during ZIP extraction
* Explicit Zipslip handling during ZIP extraction
* Graceful files extraction on unzip failure
* Removed bail out and continue analysis
* Moved androguard parsing to the start of static analysis
* AndroidManifest.xml fallback from apktool to androguard during extraction and parsing
* Updated Tasks UI to show started at
2024-11-28 17:26:50 -08:00

523 lines
17 KiB
Python
Executable File

# -*- coding: utf_8 -*-
"""
Shared Functions.
Module providing the shared functions for iOS and Android
"""
import hashlib
import logging
import os
import platform
import re
import shutil
import subprocess
import zipfile
from pathlib import Path
import arpy
from django.utils.html import escape
from django.http import HttpResponseRedirect
from mobsf.MobSF import settings
from mobsf.MobSF.security import (
sanitize_for_logging,
)
from mobsf.MobSF.utils import (
EMAIL_REGEX,
STRINGS_REGEX,
URL_REGEX,
append_scan_status,
is_md5,
is_path_traversal,
is_safe_path,
print_n_send_error_response,
set_permissions,
)
from mobsf.MobSF.views.scanning import (
add_to_recent_scan,
handle_uploaded_file,
)
from mobsf.StaticAnalyzer.views.comparer import (
generic_compare,
)
from mobsf.StaticAnalyzer.views.common.entropy import (
get_entropies,
)
from mobsf.MobSF.views.authentication import (
login_required,
)
from mobsf.MobSF.views.authorization import (
Permissions,
permission_required,
)
logger = logging.getLogger(__name__)
RESERVED_FILE_NAMES = [
'AndroidManifest.xml',
'resources.arsc',
'META-INF/MANIFEST.MF',
'META-INF/CERT.SF',
'META-INF/CERT.RSA',
'META-INF/CERT.DSA',
'classes.dex']
for i in range(2, 50):
RESERVED_FILE_NAMES.append(f'classes{i}.dex')
def hash_gen(checksum, app_path) -> tuple:
"""Generate and return sha1 and sha256 as a tuple."""
try:
msg = 'Generating Hashes'
logger.info(msg)
append_scan_status(checksum, msg)
sha1 = hashlib.sha1()
sha256 = hashlib.sha256()
block_size = 65536
with open(app_path, mode='rb') as afile:
buf = afile.read(block_size)
while buf:
sha1.update(buf)
sha256.update(buf)
buf = afile.read(block_size)
sha1val = sha1.hexdigest()
sha256val = sha256.hexdigest()
return sha1val, sha256val
except Exception as exp:
msg = 'Failed to generate Hashes'
logger.exception(msg)
append_scan_status(checksum, msg, repr(exp))
def is_reserved_file_conflict(file_path):
"""Check for reserved file conflict."""
if any(file_path.startswith(i) and file_path != i for i in RESERVED_FILE_NAMES):
return True
return False
def unzip(checksum, app_path, ext_path):
"""Unzip APK.
Unzip a APK archive while handling encrypted files, reserved file conflicts,
path traversal (Zip Slip), and permission adjustments. Some of the anti-analysis
techniques used by malware authors and packers are handled here.
Args:
checksum (str): The checksum of the file.
app_path (str): Path to the ZIP archive.
ext_path (str): Path to extract the files.
Returns:
list: A list of files extracted or an empty list if an error occurs.
"""
msg = 'Unzipping'
logger.info(msg)
append_scan_status(checksum, msg)
files = []
original_ext_path = ext_path
try:
with zipfile.ZipFile(app_path, 'r') as zipptr:
files = zipptr.namelist()
for fileinfo in zipptr.infolist():
ext_path = original_ext_path
# Skip encrypted files
if fileinfo.flag_bits & 0x1:
msg = ('Skipping encrypted file '
f'{sanitize_for_logging(fileinfo.filename)}')
logger.warning(msg)
continue
file_path = fileinfo.filename.rstrip('/\\') # Remove trailing slashes
# Decode the filename
if not isinstance(file_path, str):
file_path = file_path.decode('utf-8', errors='replace')
# Check for reserved file conflict
if is_reserved_file_conflict(file_path):
ext_path = str(Path(ext_path) / '_conflict_')
# Handle Zip Slip
if is_path_traversal(file_path):
msg = ('Zip slip detected. skipped extracting'
f' {sanitize_for_logging(file_path)}')
logger.error(msg)
continue
# Fix permissions
if fileinfo.is_dir():
# Directories should have rwxr-xr-x (755)
# Skip creating directories
continue
else:
# Files should have rw-r--r-- (644)
fileinfo.external_attr = (0o100644 << 16) | (
fileinfo.external_attr & 0xFFFF)
# Extract the file
try:
zipptr.extract(file_path, ext_path)
except Exception:
logger.warning(
'Failed to extract %s', sanitize_for_logging(file_path))
except Exception as exp:
msg = f'Unzipping Error - {str(exp)}'
logger.error(msg)
append_scan_status(checksum, msg, repr(exp))
# Fallback to OS unzip
ofiles = os_unzip(checksum, app_path, ext_path)
if not files:
files = ofiles
return files
def os_unzip(checksum, app_path, ext_path):
"""Unzip using OS utility."""
msg = 'Attempting to unzip with OS unzip utility'
logger.info(msg)
append_scan_status(checksum, msg)
try:
if platform.system() == 'Windows':
msg = 'Unzipping Error. Not yet implemented in Windows'
logger.warning(msg)
append_scan_status(checksum, msg)
return []
unzip_b = shutil.which('unzip')
if not unzip_b:
msg = 'OS Unzip utility not found'
logger.warning(msg)
append_scan_status(checksum, msg)
return []
subprocess.call(
[unzip_b, '-o', '-q', app_path, '-d', ext_path])
# Set permissions, packed files
# may not have proper permissions
set_permissions(ext_path)
# List files in the unzipped directory
dat = subprocess.check_output([unzip_b, '-qq', '-l', app_path])
dat = dat.decode('utf-8').split('\n')
files_det = ['Length Date Time Name']
return files_det + dat
except Exception as exp:
msg = 'Unzipping Error with OS unzip utility'
logger.exception(msg)
append_scan_status(checksum, msg, repr(exp))
return []
def lipo_thin(checksum, src, dst):
"""Thin Fat binary."""
new_src = None
try:
msg = 'Thinning Fat binary'
logger.info(msg)
append_scan_status(checksum, msg)
lipo = shutil.which('lipo')
out = Path(dst) / (Path(src).stem + '_thin.a')
new_src = out.as_posix()
archs = [
'armv7', 'armv6', 'arm64', 'x86_64',
'armv4t', 'armv5', 'armv6m', 'armv7f',
'armv7s', 'armv7k', 'armv7m', 'armv7em',
'arm64v8']
for arch in archs:
args = [
lipo,
src,
'-thin',
arch,
'-output',
new_src]
out = subprocess.run(
args,
stdout=subprocess.DEVNULL,
stderr=subprocess.STDOUT)
if out.returncode == 0:
break
except Exception as exp:
msg = 'lipo Fat binary thinning failed'
logger.warning(msg)
append_scan_status(checksum, msg, repr(exp))
return new_src
def ar_os(src, dst):
out = ''
"""Extract AR using OS utility."""
cur = os.getcwd()
try:
os.chdir(dst)
out = subprocess.check_output(
[shutil.which('ar'), 'x', src],
stderr=subprocess.STDOUT)
except Exception as exp:
out = exp.output
finally:
os.chdir(cur)
return out
def ar_extract(checksum, src, dst):
"""Extract AR archive."""
msg = 'Extracting static library archive'
logger.info(msg)
append_scan_status(checksum, msg)
try:
ar = arpy.Archive(src)
ar.read_all_headers()
for a, val in ar.archived_files.items():
# Handle archive slip attacks
filtered = a.decode('utf-8', 'ignore')
if is_path_traversal(filtered):
msg = f'Zip slip detected. skipped extracting {filtered}'
logger.warning(msg)
append_scan_status(checksum, msg)
continue
out = Path(dst) / filtered
out.write_bytes(val.read())
except Exception:
# Possibly dealing with Fat binary, needs Mac host
msg = 'Failed to extract .a archive'
logger.warning(msg)
append_scan_status(checksum, msg)
# Use os ar utility
plat = platform.system()
os_err = 'Possibly a Fat binary. Requires MacOS for Analysis'
if plat == 'Windows':
logger.warning(os_err)
append_scan_status(checksum, os_err)
return
msg = 'Using OS ar utility to handle archive'
logger.info(msg)
append_scan_status(checksum, msg)
exp = ar_os(src, dst)
if len(exp) > 3 and plat == 'Linux':
# Can't convert FAT binary in Linux
logger.warning(os_err)
append_scan_status(checksum, os_err)
return
if b'lipo(1)' in exp:
msg = 'Fat binary archive identified'
logger.info(msg)
append_scan_status(checksum, msg)
# Fat binary archive
try:
nw_src = lipo_thin(checksum, src, dst)
if nw_src:
ar_os(nw_src, dst)
except Exception as exp:
msg = 'Failed to thin fat archive'
logger.exception(msg)
append_scan_status(checksum, msg, repr(exp))
def url_n_email_extract(dat, relative_path):
"""Extract URLs and Emails from Source Code."""
urls = set()
emails = set()
urllist = []
url_n_file = []
email_n_file = []
# URL Extraction
urllist = URL_REGEX.findall(dat.lower())
for url in urllist:
urls.add(url)
if urls:
url_n_file.append({
'urls': list(urls),
'path': escape(relative_path)})
# Email Extraction
for email in EMAIL_REGEX.findall(dat.lower()):
if not email.startswith('//'):
emails.add(email)
if emails:
email_n_file.append({
'emails': list(emails),
'path': escape(relative_path)})
return urllist, url_n_file, email_n_file
# This is just the first sanity check that triggers generic_compare
@login_required
def compare_apps(request, hash1: str, hash2: str, api=False):
if hash1 == hash2:
error_msg = 'Results with same hash cannot be compared'
return print_n_send_error_response(request, error_msg, api)
# Second Validation for REST API
if not (is_md5(hash1) and is_md5(hash2)):
error_msg = 'Invalid hashes'
return print_n_send_error_response(request, error_msg, api)
logger.info(
'Starting App compare for %s and %s', hash1, hash2)
return generic_compare(request, hash1, hash2, api)
def get_avg_cvss(findings):
# Average CVSS Score
cvss_scores = []
avg_cvss = 0
for finding in findings.values():
find = finding.get('metadata')
if not find:
# Hack to support iOS Binary Scan Results
find = finding
if find.get('cvss'):
if find['cvss'] != 0:
cvss_scores.append(find['cvss'])
if cvss_scores:
avg_cvss = round(sum(cvss_scores) / len(cvss_scores), 1)
if not getattr(settings, 'CVSS_SCORE_ENABLED', False):
avg_cvss = None
return avg_cvss
def find_java_source_folder(base_folder: Path):
# Find the correct java/kotlin source folder for APK/source zip
# Returns a Tuple of - (SRC_PATH, SRC_TYPE, SRC_SYNTAX)
return next(p for p in [(base_folder / 'java_source',
'java', '*.java'),
(base_folder / 'app' / 'src' / 'main' / 'java',
'java', '*.java'),
(base_folder / 'app' / 'src' / 'main' / 'kotlin',
'kotlin', '*.kt'),
(base_folder / 'src',
'java', '*.java')]
if p[0].exists())
def is_secret_key(key):
"""Check if the key in the key/value pair is interesting."""
key_lower = key.lower()
# Key ends with these strings
endswith = (
'api', 'key', 'secret', 'token', 'username',
'user_name', 'user', 'pass', 'password',
'private_key', 'access_key',
)
# Key contains these strings
contains = (
'api_', 'key_', 'aws', 's3_', '_s3', 'secret_',
'bearer', 'jwt', 'certificate"', 'credential',
'azure', 'webhook', 'twilio_', 'bitcoin',
'_auth', 'firebase', 'oauth', 'authorization',
'private', 'pwd', 'session', 'token_', 'gcp',
)
# Key must not contain these strings
not_string = (
'label_', 'text', 'hint', 'msg_', 'create_',
'message', 'new', 'confirm', 'activity_',
'forgot', 'dashboard_', 'current_', 'signup',
'sign_in', 'signin', 'title_', 'welcome_',
'change_', 'this_', 'the_', 'placeholder',
'invalid_', 'btn_', 'action_', 'prompt_',
'lable', 'hide_', 'old', 'update', 'error',
'empty', 'txt_', 'lbl_',
)
not_contains_str = any(i in key_lower for i in not_string)
contains_str = any(i in key_lower for i in contains)
endswith_str = any(key_lower.endswith(i) for i in endswith)
return (endswith_str or contains_str) and not not_contains_str
def strings_and_entropies(checksum, src, exts):
"""Get Strings and Entropies."""
msg = 'Extracting String values and entropies from Code'
logger.info(msg)
append_scan_status(checksum, msg)
data = {
'strings': set(),
'secrets': set(),
}
try:
if not (src and src.exists()):
return data
excludes = ('\\u0', 'com.google.')
eslash = ('Ljava', 'Lkotlin', 'kotlin', 'android')
for p in src.rglob('*'):
if p.suffix not in exts or not p.exists():
continue
matches = STRINGS_REGEX.finditer(
p.read_text(encoding='utf-8', errors='ignore'),
re.MULTILINE)
for match in matches:
string = match.group()
if len(string) < 4:
continue
if any(i in string for i in excludes):
continue
if any(i in string and '/' in string for i in eslash):
continue
if not string[0].isalnum():
continue
data['strings'].add(string)
if data['strings']:
data['secrets'] = get_entropies(data['strings'])
except Exception as exp:
msg = 'Failed to extract String values and entropies from Code'
logger.exception(msg)
append_scan_status(checksum, msg, repr(exp))
return data
def get_symbols(symbols):
all_symbols = []
for i in symbols:
for _, val in i.items():
all_symbols.extend(val)
return list(set(all_symbols))
@login_required
@permission_required(Permissions.SCAN)
def scan_library(request, checksum):
"""Scan a shared library or framework from path name."""
try:
libchecksum = None
if not is_md5(checksum):
return print_n_send_error_response(
request,
'Invalid MD5')
relative_path = request.GET['library']
lib_dir = Path(settings.UPLD_DIR) / checksum
sfile = lib_dir / relative_path
if not is_safe_path(lib_dir.as_posix(), sfile.as_posix()):
msg = 'Path Traversal Detected!'
return print_n_send_error_response(request, msg)
ext = sfile.suffix
if not ext and 'Frameworks' in relative_path:
# Force Dylib on Frameworks
ext = '.dylib'
if not sfile.exists():
msg = 'Library File not found'
return print_n_send_error_response(request, msg)
with open(sfile, 'rb') as f:
libchecksum = handle_uploaded_file(f, ext)
if ext in [f'.{i}' for i in settings.IOS_EXTS]:
static_analyzer = 'static_analyzer_ios'
elif ext == '.appx':
# Not applicable, but still set it
static_analyzer = 'windows_static_analyzer'
elif ext in [f'.{i}' for i in settings.ANDROID_EXTS]:
static_analyzer = 'static_analyzer'
else:
msg = 'Extension not supported'
return print_n_send_error_response(request, msg)
data = {
'analyzer': static_analyzer,
'status': 'success',
'hash': libchecksum,
'scan_type': ext.replace('.', ''),
'file_name': sfile.name,
}
add_to_recent_scan(data)
return HttpResponseRedirect(f'/{static_analyzer}/{libchecksum}/')
except Exception:
msg = 'Failed to perform Static Analysis of library'
logger.exception(msg)
return print_n_send_error_response(request, msg)