498 lines
19 KiB
Python
498 lines
19 KiB
Python
"""Python STIX2 Environment API."""
|
|
|
|
import copy
|
|
import logging
|
|
import math
|
|
import time
|
|
|
|
from .core import parse as _parse
|
|
from .datastore import CompositeDataSource, DataStoreMixin
|
|
from .utils import STIXdatetime, parse_into_datetime
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
class ObjectFactory(object):
|
|
"""Easily create STIX objects with default values for certain properties.
|
|
|
|
Args:
|
|
created_by_ref (optional): Default created_by_ref value to apply to all
|
|
objects created by this factory.
|
|
created (optional): Default created value to apply to all
|
|
objects created by this factory.
|
|
external_references (optional): Default `external_references` value to apply
|
|
to all objects created by this factory.
|
|
object_marking_refs (optional): Default `object_marking_refs` value to apply
|
|
to all objects created by this factory.
|
|
list_append (bool, optional): When a default is set for a list property like
|
|
`external_references` or `object_marking_refs` and a value for
|
|
that property is passed into `create()`, if this is set to True,
|
|
that value will be added to the list alongside the default. If
|
|
this is set to False, the passed in value will replace the
|
|
default. Defaults to True.
|
|
"""
|
|
|
|
def __init__(
|
|
self, created_by_ref=None, created=None,
|
|
external_references=None, object_marking_refs=None,
|
|
list_append=True,
|
|
):
|
|
|
|
self._defaults = {}
|
|
if created_by_ref:
|
|
self.set_default_creator(created_by_ref)
|
|
if created:
|
|
self.set_default_created(created)
|
|
if external_references:
|
|
self.set_default_external_refs(external_references)
|
|
if object_marking_refs:
|
|
self.set_default_object_marking_refs(object_marking_refs)
|
|
self._list_append = list_append
|
|
self._list_properties = ['external_references', 'object_marking_refs']
|
|
|
|
def set_default_creator(self, creator=None):
|
|
"""Set default value for the `created_by_ref` property.
|
|
|
|
"""
|
|
self._defaults['created_by_ref'] = creator
|
|
|
|
def set_default_created(self, created=None):
|
|
"""Set default value for the `created` property.
|
|
|
|
"""
|
|
self._defaults['created'] = created
|
|
# If the user provides a default "created" time, we also want to use
|
|
# that as the modified time.
|
|
self._defaults['modified'] = created
|
|
|
|
def set_default_external_refs(self, external_references=None):
|
|
"""Set default external references.
|
|
|
|
"""
|
|
self._defaults['external_references'] = external_references
|
|
|
|
def set_default_object_marking_refs(self, object_marking_refs=None):
|
|
"""Set default object markings.
|
|
|
|
"""
|
|
self._defaults['object_marking_refs'] = object_marking_refs
|
|
|
|
def create(self, cls, **kwargs):
|
|
"""Create a STIX object using object factory defaults.
|
|
|
|
Args:
|
|
cls: the python-stix2 class of the object to be created (eg. Indicator)
|
|
**kwargs: The property/value pairs of the STIX object to be created
|
|
"""
|
|
|
|
# Use self.defaults as the base, but update with any explicit args
|
|
# provided by the user.
|
|
properties = copy.deepcopy(self._defaults)
|
|
if kwargs:
|
|
if self._list_append:
|
|
# Append provided items to list properties instead of replacing them
|
|
for list_prop in set(self._list_properties).intersection(kwargs.keys(), properties.keys()):
|
|
kwarg_prop = kwargs.pop(list_prop)
|
|
if kwarg_prop is None:
|
|
del properties[list_prop]
|
|
continue
|
|
if not isinstance(properties[list_prop], list):
|
|
properties[list_prop] = [properties[list_prop]]
|
|
|
|
if isinstance(kwarg_prop, list):
|
|
properties[list_prop].extend(kwarg_prop)
|
|
else:
|
|
properties[list_prop].append(kwarg_prop)
|
|
|
|
properties.update(**kwargs)
|
|
|
|
return cls(**properties)
|
|
|
|
|
|
class Environment(DataStoreMixin):
|
|
"""Abstract away some of the nasty details of working with STIX content.
|
|
|
|
Args:
|
|
factory (ObjectFactory, optional): Factory for creating objects with common
|
|
defaults for certain properties.
|
|
store (DataStore, optional): Data store providing the source and sink for the
|
|
environment.
|
|
source (DataSource, optional): Source for retrieving STIX objects.
|
|
sink (DataSink, optional): Destination for saving STIX objects.
|
|
Invalid if `store` is also provided.
|
|
|
|
.. automethod:: get
|
|
.. automethod:: all_versions
|
|
.. automethod:: query
|
|
.. automethod:: creator_of
|
|
.. automethod:: relationships
|
|
.. automethod:: related_to
|
|
.. automethod:: add
|
|
|
|
"""
|
|
|
|
def __init__(self, factory=ObjectFactory(), store=None, source=None, sink=None):
|
|
self.factory = factory
|
|
self.source = CompositeDataSource()
|
|
if store:
|
|
self.source.add_data_source(store.source)
|
|
self.sink = store.sink
|
|
if source:
|
|
self.source.add_data_source(source)
|
|
if sink:
|
|
if store:
|
|
raise ValueError("Data store already provided! Environment may only have one data sink.")
|
|
self.sink = sink
|
|
|
|
def create(self, *args, **kwargs):
|
|
return self.factory.create(*args, **kwargs)
|
|
create.__doc__ = ObjectFactory.create.__doc__
|
|
|
|
def set_default_creator(self, *args, **kwargs):
|
|
return self.factory.set_default_creator(*args, **kwargs)
|
|
set_default_creator.__doc__ = ObjectFactory.set_default_creator.__doc__
|
|
|
|
def set_default_created(self, *args, **kwargs):
|
|
return self.factory.set_default_created(*args, **kwargs)
|
|
set_default_created.__doc__ = ObjectFactory.set_default_created.__doc__
|
|
|
|
def set_default_external_refs(self, *args, **kwargs):
|
|
return self.factory.set_default_external_refs(*args, **kwargs)
|
|
set_default_external_refs.__doc__ = ObjectFactory.set_default_external_refs.__doc__
|
|
|
|
def set_default_object_marking_refs(self, *args, **kwargs):
|
|
return self.factory.set_default_object_marking_refs(*args, **kwargs)
|
|
set_default_object_marking_refs.__doc__ = ObjectFactory.set_default_object_marking_refs.__doc__
|
|
|
|
def add_filters(self, *args, **kwargs):
|
|
return self.source.filters.add(*args, **kwargs)
|
|
|
|
def add_filter(self, *args, **kwargs):
|
|
return self.source.filters.add(*args, **kwargs)
|
|
|
|
def parse(self, *args, **kwargs):
|
|
return _parse(*args, **kwargs)
|
|
parse.__doc__ = _parse.__doc__
|
|
|
|
def creator_of(self, obj):
|
|
"""Retrieve the Identity refered to by the object's `created_by_ref`.
|
|
|
|
Args:
|
|
obj: The STIX object whose `created_by_ref` property will be looked
|
|
up.
|
|
|
|
Returns:
|
|
str: The STIX object's creator, or None, if the object contains no
|
|
`created_by_ref` property or the object's creator cannot be
|
|
found.
|
|
|
|
"""
|
|
creator_id = obj.get('created_by_ref', '')
|
|
if creator_id:
|
|
return self.get(creator_id)
|
|
else:
|
|
return None
|
|
|
|
@staticmethod
|
|
def semantically_equivalent(obj1, obj2, **weight_dict):
|
|
"""This method is meant to verify if two objects of the same type are
|
|
semantically equivalent.
|
|
|
|
Args:
|
|
obj1: A stix2 object instance
|
|
obj2: A stix2 object instance
|
|
weight_dict: A dictionary that can be used to override settings
|
|
in the semantic equivalence process
|
|
|
|
Returns:
|
|
float: A number between 0.0 and 100.0 as a measurement of equivalence.
|
|
|
|
Warnings:
|
|
Not all objects are supported.
|
|
|
|
Notes:
|
|
This implementation follows the Committee Note on semantic equivalence.
|
|
see `the Committee Note <link here>`__.
|
|
|
|
"""
|
|
# default weights used for the semantic equivalence process
|
|
weigths = {
|
|
"attack-pattern": {
|
|
"name": 30,
|
|
"external_references": 70,
|
|
},
|
|
"campaign": {
|
|
"name": 60,
|
|
"aliases": 40,
|
|
},
|
|
"identity": {
|
|
"name": 60,
|
|
"identity_class": 20,
|
|
"sectors": 20,
|
|
},
|
|
"indicator": {
|
|
"indicator_types": 15,
|
|
"pattern": 80,
|
|
"valid_from": 5,
|
|
},
|
|
"location": {
|
|
"longitude_latitude": 34,
|
|
"region": 33,
|
|
"country": 33,
|
|
},
|
|
"malware": {
|
|
"malware_types": 20,
|
|
"name": 80,
|
|
},
|
|
"threat-actor": {
|
|
"name": 60,
|
|
"threat_actor_types": 20,
|
|
"aliases": 20,
|
|
},
|
|
"tool": {
|
|
"tool_types": 20,
|
|
"name": 80,
|
|
},
|
|
"vulnerability": {
|
|
"name": 30,
|
|
"external_references": 70,
|
|
},
|
|
"_internal": {
|
|
"tdelta": 1, # One day interval
|
|
},
|
|
}
|
|
|
|
if weight_dict:
|
|
weigths.update(weight_dict)
|
|
|
|
matching_score = 0.0
|
|
sum_weights = 0.0
|
|
type1, type2 = obj1["type"], obj2["type"]
|
|
|
|
if type1 != type2:
|
|
raise ValueError('The objects to compare must be of the same type!')
|
|
|
|
if obj1.get("spec_version", "2.0") != obj2.get("spec_version", "2.0"):
|
|
raise ValueError('The objects to compare must be of the same spec version!')
|
|
|
|
if type1 == "attack-pattern":
|
|
if _check_property_present("name", obj1, obj2):
|
|
w = weigths["attack-pattern"]["name"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_string_based(obj1["name"], obj2["name"])
|
|
if _check_property_present("external_references", obj1, obj2):
|
|
w = weigths["attack-pattern"]["external_references"]
|
|
sum_weights += w
|
|
matching_score += (
|
|
w *
|
|
_partial_external_reference_based(obj1["external_references"], obj2["external_references"])
|
|
)
|
|
|
|
elif type1 == "campaign":
|
|
if _check_property_present("name", obj1, obj2):
|
|
w = weigths["campaign"]["name"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_string_based(obj1["name"], obj2["name"])
|
|
if _check_property_present("aliases", obj1, obj2):
|
|
w = weigths["campaign"]["aliases"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_list_based(obj1["aliases"], obj2["aliases"])
|
|
|
|
elif type1 == "course-of-action":
|
|
logger.warning("%s type has no semantic equivalence implementation", type1)
|
|
return 0
|
|
|
|
elif type1 == "identity":
|
|
if _check_property_present("name", obj1, obj2):
|
|
w = weigths["identity"]["name"]
|
|
sum_weights += w
|
|
matching_score += w * _exact_match(obj1["name"], obj2["name"])
|
|
if _check_property_present("identity_class", obj1, obj2):
|
|
w = weigths["identity"]["identity_class"]
|
|
sum_weights += w
|
|
matching_score += w * _exact_match(obj1["identity_class"], obj2["identity_class"])
|
|
if _check_property_present("sectors", obj1, obj2):
|
|
w = weigths["identity"]["sectors"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_list_based(obj1["sectors"], obj2["sectors"])
|
|
|
|
elif type1 == "indicator":
|
|
if _check_property_present("indicator_types", obj1, obj2):
|
|
w = weigths["indicator"]["indicator_types"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_list_based(obj1["indicator_types"], obj2["indicator_types"])
|
|
if _check_property_present("pattern", obj1, obj2):
|
|
w = weigths["indicator"]["pattern"]
|
|
sum_weights += w
|
|
matching_score += w * _custom_pattern_based(obj1["pattern"], obj2["pattern"])
|
|
if _check_property_present("valid_from", obj1, obj2):
|
|
w = weigths["indicator"]["valid_from"]
|
|
sum_weights += w
|
|
matching_score += (
|
|
w *
|
|
_partial_timestamp_based(obj1["valid_from"], obj2["valid_from"], weigths["_internal"]["tdelta"])
|
|
)
|
|
|
|
elif type1 == "intrusion-set":
|
|
logger.warning("%s type has no semantic equivalence implementation", type1)
|
|
return 0
|
|
|
|
elif type1 == "location":
|
|
if _check_property_present("latitude", obj1, obj2) and _check_property_present("longitude", obj1, obj2):
|
|
w = weigths["location"]["longitude_latitude"]
|
|
sum_weights += w
|
|
matching_score += (
|
|
w *
|
|
_partial_location_distance(obj1["latitude"], obj1["longitude"], obj2["latitude"], obj2["longitude"])
|
|
)
|
|
if _check_property_present("region", obj1, obj2):
|
|
w = weigths["location"]["region"]
|
|
sum_weights += w
|
|
matching_score += w * _exact_match(obj1["region"], obj2["region"])
|
|
if _check_property_present("country", obj1, obj2):
|
|
w = weigths["location"]["country"]
|
|
sum_weights += w
|
|
matching_score += w * _exact_match(obj1["country"], obj2["country"])
|
|
|
|
elif type1 == "malware":
|
|
if _check_property_present("malware_types", obj1, obj2):
|
|
w = weigths["malware"]["malware_types"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_list_based(obj1["malware_types"], obj2["malware_types"])
|
|
if _check_property_present("name", obj1, obj2):
|
|
w = weigths["malware"]["name"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_string_based(obj1["name"], obj2["name"])
|
|
|
|
elif type1 == "observed-data":
|
|
logger.warning("%s type has no semantic equivalence implementation", type1)
|
|
return 0
|
|
|
|
elif type1 == "report":
|
|
logger.warning("%s type has no semantic equivalence implementation", type1)
|
|
return 0
|
|
|
|
elif type1 == "threat-actor":
|
|
if _check_property_present("name", obj1, obj2):
|
|
w = weigths["threat-actor"]["name"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_string_based(obj1["name"], obj2["name"])
|
|
if _check_property_present("threat_actor_types", obj1, obj2):
|
|
w = weigths["threat-actor"]["threat_actor_types"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_list_based(obj1["threat_actor_types"], obj2["threat_actor_types"])
|
|
if _check_property_present("aliases", obj1, obj2):
|
|
w = weigths["threat-actor"]["aliases"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_list_based(obj1["aliases"], obj2["aliases"])
|
|
|
|
elif type1 == "tool":
|
|
if _check_property_present("tool_types", obj1, obj2):
|
|
w = weigths["tool"]["tool_types"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_list_based(obj1["tool_types"], obj2["tool_types"])
|
|
if _check_property_present("name", obj1, obj2):
|
|
w = weigths["tool"]["name"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_string_based(obj1["name"], obj2["name"])
|
|
|
|
elif type1 == "vulnerability":
|
|
if _check_property_present("name", obj1, obj2):
|
|
w = weigths["vulnerability"]["name"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_string_based(obj1["name"], obj2["name"])
|
|
if _check_property_present("external_references", obj1, obj2):
|
|
w = weigths["vulnerability"]["external_references"]
|
|
sum_weights += w
|
|
matching_score += w * _partial_external_reference_based(obj1["external_references"], obj2["external_references"])
|
|
|
|
if sum_weights <= 0:
|
|
return 0
|
|
|
|
equivalence_score = (matching_score / sum_weights) * 100.0
|
|
return equivalence_score
|
|
|
|
|
|
def _check_property_present(prop, obj1, obj2):
|
|
if prop in obj1 and prop in obj2:
|
|
return True
|
|
return False
|
|
|
|
|
|
def _partial_timestamp_based(t1, t2, tdelta):
|
|
if not isinstance(t1, STIXdatetime):
|
|
t1 = parse_into_datetime(t1)
|
|
if not isinstance(t2, STIXdatetime):
|
|
t2 = parse_into_datetime(t2)
|
|
t1, t2 = time.mktime(t1.timetuple()), time.mktime(t2.timetuple())
|
|
return 1 - min(abs(t1 - t2) / (86400 * tdelta), 1)
|
|
|
|
|
|
def _partial_list_based(l1, l2):
|
|
l1_set, l2_set = set(l1), set(l2)
|
|
return len(l1_set.intersection(l2_set)) / max(len(l1), len(l2))
|
|
|
|
|
|
def _exact_match(val1, val2):
|
|
if val1 == val2:
|
|
return 1.0
|
|
return 0.0
|
|
|
|
|
|
def _partial_string_based(str1, str2):
|
|
from pyjarowinkler import distance
|
|
return distance.get_jaro_distance(str1, str2)
|
|
|
|
|
|
def _custom_pattern_based(pattern1, pattern2):
|
|
logger.warning("Checking for Indicator pattern equivalence is currently not implemented!")
|
|
return 0 # TODO: Needs to be implemented
|
|
|
|
|
|
def _partial_external_reference_based(refs1, refs2):
|
|
allowed = set(("veris", "cve", "capec", "mitre-attack"))
|
|
matches = 0
|
|
|
|
if len(refs1) >= len(refs2):
|
|
l1 = refs1
|
|
l2 = refs2
|
|
else:
|
|
l1 = refs2
|
|
l2 = refs1
|
|
|
|
for ext_ref1 in l1:
|
|
for ext_ref2 in l2:
|
|
sn_match = False
|
|
ei_match = False
|
|
url_match = False
|
|
source_name = None
|
|
|
|
if _check_property_present("source_name", ext_ref1, ext_ref2):
|
|
if ext_ref1["source_name"] == ext_ref2["source_name"]:
|
|
source_name = ext_ref1["source_name"]
|
|
sn_match = True
|
|
if _check_property_present("external_id", ext_ref1, ext_ref2):
|
|
if ext_ref1["external_id"] == ext_ref2["external_id"]:
|
|
ei_match = True
|
|
if _check_property_present("url", ext_ref1, ext_ref2):
|
|
if ext_ref1["url"] == ext_ref2["url"]:
|
|
url_match = True
|
|
|
|
# Special case: if source_name is a STIX defined name and either
|
|
# external_id or url match then its a perfect match and other entries
|
|
# can be ignored.
|
|
if sn_match and (ei_match or url_match) and source_name in allowed:
|
|
return 1.0
|
|
|
|
# Regular check. If the source_name (not STIX-defined) or external_id or
|
|
# url matches then we consider the entry a match.
|
|
if (sn_match or ei_match or url_match) and source_name not in allowed:
|
|
matches += 1
|
|
|
|
return matches / max(len(refs1), len(refs2))
|
|
|
|
|
|
def _partial_location_distance(lat1, long1, lat2, long2):
|
|
distance = math.sqrt(((lat2 - lat1) ** 2) + ((long2 - long1) ** 2))
|
|
return 1 - (distance / 1000.0)
|