mirror of
https://github.com/mvt-project/mvt.git
synced 2024-06-28 07:09:00 +00:00
236 lines
8.2 KiB
Python
236 lines
8.2 KiB
Python
# Mobile Verification Toolkit (MVT)
|
|
# Copyright (c) 2021 The MVT Project Authors.
|
|
# Use of this software is governed by the MVT License 1.1 that can be found at
|
|
# https://license.mvt.re/1.1/
|
|
|
|
import json
|
|
import os
|
|
|
|
from .url import URL
|
|
|
|
|
|
class IndicatorsFileBadFormat(Exception):
|
|
pass
|
|
|
|
class Indicators:
|
|
"""This class is used to parse indicators from a STIX2 file and provide
|
|
functions to compare extracted artifacts to the indicators.
|
|
"""
|
|
|
|
def __init__(self, log=None):
|
|
self.log = log
|
|
self.ioc_domains = []
|
|
self.ioc_processes = []
|
|
self.ioc_emails = []
|
|
self.ioc_files = []
|
|
self.ioc_count = 0
|
|
|
|
def _add_indicator(self, ioc, iocs_list):
|
|
if ioc not in iocs_list:
|
|
iocs_list.append(ioc)
|
|
self.ioc_count += 1
|
|
|
|
def parse_stix2(self, file_path):
|
|
"""Extract indicators from a STIX2 file.
|
|
|
|
:param file_path: Path to the STIX2 file to parse
|
|
:type file_path: str
|
|
"""
|
|
self.log.info("Parsing STIX2 indicators file at path %s",
|
|
file_path)
|
|
|
|
with open(file_path, "r") as handle:
|
|
try:
|
|
data = json.load(handle)
|
|
except json.decoder.JSONDecodeError:
|
|
raise IndicatorsFileBadFormat("Unable to parse STIX2 indicators file, the file seems malformed or in the wrong format")
|
|
|
|
for entry in data.get("objects", []):
|
|
if entry.get("type", "") != "indicator":
|
|
continue
|
|
|
|
key, value = entry.get("pattern", "").strip("[]").split("=")
|
|
value = value.strip("'")
|
|
|
|
if key == "domain-name:value":
|
|
# We force domain names to lower case.
|
|
self._add_indicator(ioc=value.lower(),
|
|
iocs_list=self.ioc_domains)
|
|
elif key == "process:name":
|
|
self._add_indicator(ioc=value,
|
|
iocs_list=self.ioc_processes)
|
|
elif key == "email-addr:value":
|
|
# We force email addresses to lower case.
|
|
self._add_indicator(ioc=value.lower(),
|
|
iocs_list=self.ioc_emails)
|
|
elif key == "file:name":
|
|
self._add_indicator(ioc=value,
|
|
iocs_list=self.ioc_files)
|
|
|
|
def check_domain(self, url) -> bool:
|
|
"""Check if a given URL matches any of the provided domain indicators.
|
|
|
|
:param url: URL to match against domain indicators
|
|
:type url: str
|
|
:returns: True if the URL matched an indicator, otherwise False
|
|
:rtype: bool
|
|
"""
|
|
# TODO: If the IOC domain contains a subdomain, it is not currently
|
|
# being matched.
|
|
if not url:
|
|
return False
|
|
|
|
try:
|
|
# First we use the provided URL.
|
|
orig_url = URL(url)
|
|
|
|
if orig_url.check_if_shortened():
|
|
# If it is, we try to retrieve the actual URL making an
|
|
# HTTP HEAD request.
|
|
unshortened = orig_url.unshorten()
|
|
|
|
# self.log.info("Found a shortened URL %s -> %s",
|
|
# url, unshortened)
|
|
|
|
# Now we check for any nested URL shorteners.
|
|
dest_url = URL(unshortened)
|
|
if dest_url.check_if_shortened():
|
|
# self.log.info("Original URL %s appears to shorten another shortened URL %s ... checking!",
|
|
# orig_url.url, dest_url.url)
|
|
return self.check_domain(dest_url.url)
|
|
|
|
final_url = dest_url
|
|
else:
|
|
# If it's not shortened, we just use the original URL object.
|
|
final_url = orig_url
|
|
except Exception as e:
|
|
# If URL parsing failed, we just try to do a simple substring
|
|
# match.
|
|
for ioc in self.ioc_domains:
|
|
if ioc.lower() in url:
|
|
self.log.warning("Maybe found a known suspicious domain: %s", url)
|
|
return True
|
|
|
|
# If nothing matched, we can quit here.
|
|
return False
|
|
|
|
# If all parsing worked, we start walking through available domain indicators.
|
|
for ioc in self.ioc_domains:
|
|
# First we check the full domain.
|
|
if final_url.domain.lower() == ioc:
|
|
if orig_url.is_shortened and orig_url.url != final_url.url:
|
|
self.log.warning("Found a known suspicious domain %s shortened as %s",
|
|
final_url.url, orig_url.url)
|
|
else:
|
|
self.log.warning("Found a known suspicious domain: %s", final_url.url)
|
|
|
|
return True
|
|
|
|
# Then we just check the top level domain.
|
|
if final_url.top_level.lower() == ioc:
|
|
if orig_url.is_shortened and orig_url.url != final_url.url:
|
|
self.log.warning("Found a sub-domain matching a known suspicious top level %s shortened as %s",
|
|
final_url.url, orig_url.url)
|
|
else:
|
|
self.log.warning("Found a sub-domain matching a known suspicious top level: %s", final_url.url)
|
|
|
|
return True
|
|
|
|
return False
|
|
|
|
def check_domains(self, urls) -> bool:
|
|
"""Check a list of URLs against the provided list of domain indicators.
|
|
|
|
:param urls: List of URLs to check against domain indicators
|
|
:type urls: list
|
|
:returns: True if any URL matched an indicator, otherwise False
|
|
:rtype: bool
|
|
"""
|
|
if not urls:
|
|
return False
|
|
|
|
for url in urls:
|
|
if self.check_domain(url):
|
|
return True
|
|
|
|
return False
|
|
|
|
def check_process(self, process) -> bool:
|
|
"""Check the provided process name against the list of process
|
|
indicators.
|
|
|
|
:param process: Process name to check against process indicators
|
|
:type process: str
|
|
:returns: True if process matched an indicator, otherwise False
|
|
:rtype: bool
|
|
"""
|
|
if not process:
|
|
return False
|
|
|
|
proc_name = os.path.basename(process)
|
|
if proc_name in self.ioc_processes:
|
|
self.log.warning("Found a known suspicious process name \"%s\"", process)
|
|
return True
|
|
|
|
if len(proc_name) == 16:
|
|
for bad_proc in self.ioc_processes:
|
|
if bad_proc.startswith(proc_name):
|
|
self.log.warning("Found a truncated known suspicious process name \"%s\"", process)
|
|
return True
|
|
|
|
return False
|
|
|
|
def check_processes(self, processes) -> bool:
|
|
"""Check the provided list of processes against the list of
|
|
process indicators.
|
|
|
|
:param processes: List of processes to check against process indicators
|
|
:type processes: list
|
|
:returns: True if process matched an indicator, otherwise False
|
|
:rtype: bool
|
|
"""
|
|
if not processes:
|
|
return False
|
|
|
|
for process in processes:
|
|
if self.check_process(process):
|
|
return True
|
|
|
|
return False
|
|
|
|
def check_email(self, email) -> bool:
|
|
"""Check the provided email against the list of email indicators.
|
|
|
|
:param email: Email address to check against email indicators
|
|
:type email: str
|
|
:returns: True if email address matched an indicator, otherwise False
|
|
:rtype: bool
|
|
"""
|
|
if not email:
|
|
return False
|
|
|
|
if email.lower() in self.ioc_emails:
|
|
self.log.warning("Found a known suspicious email address: \"%s\"", email)
|
|
return True
|
|
|
|
return False
|
|
|
|
def check_file(self, file_path) -> bool:
|
|
"""Check the provided file path against the list of file indicators.
|
|
|
|
:param file_path: File path or file name to check against file
|
|
indicators
|
|
:type file_path: str
|
|
:returns: True if the file path matched an indicator, otherwise False
|
|
:rtype: bool
|
|
"""
|
|
if not file_path:
|
|
return False
|
|
|
|
file_name = os.path.basename(file_path)
|
|
if file_name in self.ioc_files:
|
|
self.log.warning("Found a known suspicious file: \"%s\"", file_path)
|
|
return True
|
|
|
|
return False
|