666 lines
21 KiB
Python
666 lines
21 KiB
Python
"""
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Python STIX 2.0 Sources
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Classes:
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DataStore
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DataSink
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DataSource
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STIXCommonPropertyFilters
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TODO:Test everything
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Notes:
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add_filter(), remove_filter(), deduplicate() - if these functions remain
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the exact same for DataSource, DataSink, CompositeDataSource etc... -> just
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make those functions an interface to inherit?
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"""
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import collections
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import uuid
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from six import iteritems
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class Filter(collections.namedtuple("Filter", ['field', 'op', 'value'])):
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__slots__ = ()
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def __new__(cls, field, op, value):
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# If value is a list, convert it to a tuple so it is hashable.
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if isinstance(value, list):
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value = tuple(value)
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self = super(Filter, cls).__new__(cls, field, op, value)
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return self
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def make_id():
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return str(uuid.uuid4())
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# Currently, only STIX 2.0 common SDO fields (that are not complex objects)
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# are supported for filtering on
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STIX_COMMON_FIELDS = [
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"created",
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"created_by_ref",
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"external_references.source_name",
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"external_references.description",
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"external_references.url",
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"external_references.hashes",
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"external_references.external_id",
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"granular_markings.marking_ref",
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"granular_markings.selectors",
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"id",
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"labels",
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"modified",
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"object_marking_refs",
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"revoked",
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"type",
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"granular_markings"
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]
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# Supported filter operations
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FILTER_OPS = ['=', '!=', 'in', '>', '<', '>=', '<=']
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# Supported filter value types
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FILTER_VALUE_TYPES = [bool, dict, float, int, list, str, tuple]
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class DataStore(object):
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"""
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An implementer will create a concrete subclass from
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this abstract class for the specific data store.
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"""
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def __init__(self, name="DataStore", source=None, sink=None):
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self.name = name
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self.id_ = make_id()
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self.source = source
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self.sink = sink
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def get(self, stix_id):
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"""
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Implement:
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Translate API get() call to the appropriate DataSource call
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Args:
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stix_id (str): the id of the STIX 2.0 object to retrieve. Should
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return a single object, the most recent version of the object
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specified by the "id".
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Returns:
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stix_obj (dictionary): the STIX object to be returned
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"""
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return self.source.get(stix_id=stix_id)
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def all_versions(self, stix_id):
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"""
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Implement:
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Translate all_versions() call to the appropriate DataSource call
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Args:
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stix_id (str): the id of the STIX 2.0 object to retrieve. Should
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return a single object, the most recent version of the object
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specified by the "id".
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_composite_filters (list): list of filters passed along from
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the Composite Data Filter.
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Returns:
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stix_objs (list): a list of STIX objects (where each object is a
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STIX object)
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"""
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return self.source.all_versions(stix_id=stix_id)
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def query(self, query):
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"""
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Fill:
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Implement the specific data source API calls, processing,
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functionality required for retrieving query from the data source
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Args:
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query (list): a list of filters (which collectively are the query)
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to conduct search on.
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Returns:
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stix_objs (list): a list of STIX objects (where each object is a
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STIX object)
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"""
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return self.source.query(query=query)
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def add(self, stix_objs):
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"""
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Fill:
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-translate add() to the appropriate DataSink call()
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"""
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return self.sink.add(stix_objs=stix_objs)
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class DataSink(object):
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"""
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Abstract class for defining a data sink. Intended for subclassing into
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different sink components.
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Attributes:
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id_ (str): A unique UUIDv4 to identify this DataSink.
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name (str): The descriptive name that identifies this DataSink.
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"""
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def __init__(self, name="DataSink"):
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self.name = name
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self.id_ = make_id()
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def add(self, stix_objs):
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"""
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Fill:
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Implement the specific data sink API calls, processing,
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functionality required for adding data to the sink
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"""
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raise NotImplementedError()
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class DataSource(object):
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"""
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Abstract class for defining a data source. Intended for subclassing into
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different source components.
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Attributes:
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id_ (str): A unique UUIDv4 to identify this DataSource.
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name (str): The descriptive name that identifies this DataSource.
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filters (set): A collection of filters present in this DataSource.
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"""
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def __init__(self, name="DataSource"):
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self.name = name
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self.id_ = make_id()
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self.filters = set()
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def get(self, stix_id, _composite_filters=None):
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"""
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Fill:
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Implement the specific data source API calls, processing,
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functionality required for retrieving data from the data source
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Args:
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stix_id (str): the id of the STIX 2.0 object to retrieve. Should
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return a single object, the most recent version of the object
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specified by the "id".
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_composite_filters (list): list of filters passed along from
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the Composite Data Filter.
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Returns:
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stix_obj (dictionary): the STIX object to be returned
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"""
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raise NotImplementedError()
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def all_versions(self, stix_id, _composite_filters=None):
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"""
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Fill:
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-Similar to get() except returns list of all object versions of
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the specified "id".
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-implement the specific data source API calls, processing,
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functionality required for retrieving data from the data source
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Args:
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stix_id (str): The id of the STIX 2.0 object to retrieve. Should
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return a list of objects, all the versions of the object
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specified by the "id".
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_composite_filters (list): list of filters passed from the
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Composite Data Source
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Returns:
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stix_objs (list): a list of STIX objects (where each object is a
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STIX object)
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"""
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raise NotImplementedError()
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def query(self, query, _composite_filters=None):
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"""
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Fill:
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-implement the specific data source API calls, processing,
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functionality required for retrieving query from the data source
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Args:
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query (list): a list of filters (which collectively are the query)
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to conduct search on
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_composite_filters (list): a list of filters passed from the
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Composite Data Source
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Returns:
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"""
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raise NotImplementedError()
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def add_filters(self, filters):
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"""Add multiple filters to the DataSource.
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Args:
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filters (list): list of filters (dict) to add to the Data Source.
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"""
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for filter_ in filters:
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self.add_filter(filter_)
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def add_filter(self, filter_):
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"""Add a filter."""
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# check filter field is a supported STIX 2.0 common field
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if filter_.field not in STIX_COMMON_FIELDS:
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raise ValueError("Filter 'field' is not a STIX 2.0 common property. Currently only STIX object common properties supported")
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# check filter operator is supported
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if filter_.op not in FILTER_OPS:
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raise ValueError("Filter operation(from 'op' field) not supported")
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# check filter value type is supported
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if type(filter_.value) not in FILTER_VALUE_TYPES:
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raise ValueError("Filter 'value' type is not supported. The type(value) must be python immutable type or dictionary")
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self.filters.add(filter_)
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# TODO: Do we need a remove_filter function?
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def apply_common_filters(self, stix_objs, query):
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"""Evaluates filters against a set of STIX 2.0 objects
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Supports only STIX 2.0 common property fields
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Args:
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stix_objs (list): list of STIX objects to apply the query to
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query (list): list of filters (combined form complete query)
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Returns:
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(list): list of STIX objects that successfully evaluate against
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the query.
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"""
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filtered_stix_objs = []
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# evaluate objects against filter
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for stix_obj in stix_objs:
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clean = True
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for filter_ in query:
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# skip filter as filter was identified (when added) as
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# not a common filter
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if filter_.field not in STIX_COMMON_FIELDS:
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continue
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# check filter "field" is in STIX object - if cant be applied
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# due to STIX object, STIX object is discarded (i.e. did not
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# make it through the filter)
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if filter_.field not in stix_obj.keys():
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clean = False
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break
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try:
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match = getattr(STIXCommonPropertyFilters, filter_.field)(filter_, stix_obj)
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if not match:
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clean = False
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break
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elif match == -1:
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# error, filter operator not supported for specified field:
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pass
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except Exception as e:
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print(e)
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# if object unmarked after all filters, add it
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if clean:
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filtered_stix_objs.append(stix_obj)
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return filtered_stix_objs
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def deduplicate(self, stix_obj_list):
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"""Deduplicate a list of STIX objects to a unique set
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Reduces a set of STIX objects to unique set by looking
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at 'id' and 'modified' fields - as a unique object version
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is determined by the combination of those fields
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Args:
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stix_obj_list (list): list of STIX objects (dicts)
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Returns:
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A list with a unique set of the passed list of STIX objects.
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"""
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unique_objs = {}
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for obj in stix_obj_list:
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unique_objs[(obj['id'], obj['modified'])] = obj
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return list(unique_objs.values())
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class CompositeDataSource(DataSource):
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"""Composite Data Source
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Acts as a controller for all the defined/configured STIX Data Sources
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e.g. a user can define n Data Sources - creating Data Source (objects)
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for each. There is only one instance of this for any python STIX 2.0
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application.
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Attributes:
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name (str): The name that identifies this CompositeDataSource.
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data_sources (dict): A dictionary of DataSource objects; to be
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controlled and used by the Data Source Controller object.
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"""
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def __init__(self, name="CompositeDataSource"):
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"""
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Creates a new STIX Data Source.
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Args:
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name (str): A string containing the name to attach in the
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CompositeDataSource instance.
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"""
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super(CompositeDataSource, self).__init__(name=name)
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self.data_sources = {}
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def get(self, stix_id, _composite_filters=None):
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"""Retrieve STIX object by 'id'
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Federated retrieve method-iterates through all STIX data sources
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defined in the "data_sources" parameter. Each data source has a
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specific API retrieve-like function and associated parameters. This
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function does a federated retrieval and consolidation of the data
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returned from all the STIX data sources.
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Notes:
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A composite data source will pass its attached filters to
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each configured data source, pushing filtering to them to handle.
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Args:
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stix_id (str): the id of the STIX object to retrieve.
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_composite_filters (list): a list of filters passed from the
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Composite Data Source
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Returns:
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stix_obj (dict): the STIX object to be returned.
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"""
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all_data = []
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# for every configured Data Source, call its retrieve handler
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for ds_id, ds in iteritems(self.data_sources):
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data = ds.get(stix_id=stix_id, _composite_filters=list(self.filters))
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all_data.append(data)
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# remove duplicate versions
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if len(all_data) > 0:
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all_data = self.deduplicate(all_data)
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# reduce to most recent version
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stix_obj = sorted(all_data, key=lambda k: k['modified'], reverse=True)[0]
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return stix_obj
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def all_versions(self, stix_id, _composite_filters=None):
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"""Retrieve STIX objects by 'id'
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Federated all_versions retrieve method - iterates through all STIX data
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sources defined in "data_sources"
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Notes:
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A composite data source will pass its attached filters to
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each configured data source, pushing filtering to them to handle
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Args:
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stix_id (str): id of the STIX objects to retrieve
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_composite_filters (list): a list of filters passed from the
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Composite Data Source
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Returns:
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all_data (list): list of STIX objects that have the specified id
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"""
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all_data = []
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all_filters = self.filters
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if _composite_filters:
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all_filters = set(self.filters).update(_composite_filters)
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# retrieve STIX objects from all configured data sources
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for ds_id, ds in iteritems(self.data_sources):
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data = ds.all_versions(stix_id=stix_id, _composite_filters=list(all_filters))
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all_data.extend(data)
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# remove exact duplicates (where duplicates are STIX 2.0 objects
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# with the same 'id' and 'modified' values)
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if len(all_data) > 0:
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all_data = self.deduplicate(all_data)
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return all_data
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def query(self, query=None, _composite_filters=None):
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"""Composite data source query
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Federate the query to all Data Sources attached to the
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Composite Data Source.
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Args:
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query (list): list of filters to search on.
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_composite_filters (list): a list of filters passed from the
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Composite Data Source
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Returns:
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all_data (list): list of STIX objects to be returned
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"""
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if not query:
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query = []
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all_data = []
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all_filters = self.filters
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if _composite_filters:
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all_filters = set(self.filters).update(_composite_filters)
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# federate query to all attached data sources,
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# pass composite filters to id
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for ds_id, ds in iteritems(self.data_sources):
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data = ds.query(query=query, _composite_filters=list(all_filters))
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all_data.extend(data)
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# remove exact duplicates (where duplicates are STIX 2.0
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# objects with the same 'id' and 'modified' values)
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if len(all_data) > 0:
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all_data = self.deduplicate(all_data)
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return all_data
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def add_data_source(self, data_sources):
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"""Add/attach Data Source to the Composite Data Source instance
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Args:
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data_sources (list): a list of Data Source objects to attach
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to the Composite Data Source
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"""
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for ds in data_sources:
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if issubclass(ds.__class__, DataSource):
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if ds.id_ in self.data_sources:
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# data source already attached to Composite Data Source
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continue
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# add data source to Composite Data Source
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# (its id will be its key identifier)
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self.data_sources[ds.id_] = ds
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else:
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# the Data Source object is not a proper subclass
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# of DataSource Abstract Class
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# TODO: maybe log error?
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continue
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return
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def remove_data_source(self, data_source_ids):
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"""Remove/detach Data Source from the Composite Data Source instance
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Args:
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data_source_ids (list): a list of Data Source identifiers.
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"""
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for id_ in data_source_ids:
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if id_ in self.data_sources:
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del self.data_sources[id_]
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else:
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raise ValueError("DataSource 'id' not found in CompositeDataSource collection.")
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return
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def get_all_data_sources(self):
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"""Return all attached Data Sources
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"""
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return self.data_sources.values()
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class STIXCommonPropertyFilters(object):
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"""
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"""
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@classmethod
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def _all(cls, filter_, stix_obj_field):
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"""all filter operations (for filters whose value type can be applied to any operation type)"""
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if filter_.op == "=":
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return stix_obj_field == filter_.value
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elif filter_.op == "!=":
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return stix_obj_field != filter_.value
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elif filter_.op == "in":
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return stix_obj_field in filter_.value
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elif filter_.op == ">":
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return stix_obj_field > filter_.value
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elif filter_.op == "<":
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return stix_obj_field < filter_.value
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elif filter_.op == ">=":
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return stix_obj_field >= filter_.value
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elif filter_.op == "<=":
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return stix_obj_field <= filter_.value
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else:
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return -1
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@classmethod
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def _id(cls, filter_, stix_obj_id):
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"""base filter types"""
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if filter_.op == "=":
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return stix_obj_id == filter_.value
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elif filter_.op == "!=":
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return stix_obj_id != filter_.value
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else:
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return -1
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@classmethod
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def _boolean(cls, filter_, stix_obj_field):
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if filter_.op == "=":
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return stix_obj_field == filter_.value
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elif filter_.op == "!=":
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return stix_obj_field != filter_.value
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else:
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return -1
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@classmethod
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def _string(cls, filter_, stix_obj_field):
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return cls._all(filter_, stix_obj_field)
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@classmethod
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def _timestamp(cls, filter_, stix_obj_timestamp):
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return cls._all(filter_, stix_obj_timestamp)
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# STIX 2.0 Common Property filters
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@classmethod
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def created(cls, filter_, stix_obj):
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return cls._timestamp(filter_, stix_obj["created"])
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@classmethod
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def created_by_ref(cls, filter_, stix_obj):
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return cls._id(filter_, stix_obj["created_by_ref"])
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@classmethod
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def external_references(cls, filter_, stix_obj):
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"""
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|
STIX object's can have a list of external references
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external_references properties:
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external_references.source_name (string)
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external_references.description (string)
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external_references.url (string)
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external_references.hashes (hash, but for filtering purposes, a string)
|
|
external_references.external_id (string)
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"""
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for er in stix_obj["external_references"]:
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# grab er property name from filter field
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filter_field = filter_.field.split(".")[1]
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r = cls._string(filter_, er[filter_field])
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if r:
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|
return r
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return False
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@classmethod
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def granular_markings(cls, filter_, stix_obj):
|
|
"""
|
|
STIX object's can have a list of granular marking references
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|
|
|
granular_markings properties:
|
|
granular_markings.marking_ref (id)
|
|
granular_markings.selectors (string)
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|
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|
"""
|
|
for gm in stix_obj["granular_markings"]:
|
|
# grab gm property name from filter field
|
|
filter_field = filter_.field.split(".")[1]
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|
|
|
if filter_field == "marking_ref":
|
|
return cls._id(filter_, gm[filter_field])
|
|
|
|
elif filter_field == "selectors":
|
|
for selector in gm[filter_field]:
|
|
r = cls._string(filter_, selector)
|
|
if r:
|
|
return r
|
|
return False
|
|
|
|
@classmethod
|
|
def id(cls, filter_, stix_obj):
|
|
return cls._id(filter_, stix_obj["id"])
|
|
|
|
@classmethod
|
|
def labels(cls, filter_, stix_obj):
|
|
for label in stix_obj["labels"]:
|
|
r = cls._string(filter_, label)
|
|
if r:
|
|
return r
|
|
return False
|
|
|
|
@classmethod
|
|
def modified(cls, filter_, stix_obj):
|
|
return cls._timestamp(filter_, stix_obj["created"])
|
|
|
|
@classmethod
|
|
def object_markings_ref(cls, filter_, stix_obj):
|
|
for marking_id in stix_obj["object_market_refs"]:
|
|
r = cls._id(filter_, marking_id)
|
|
if r:
|
|
return r
|
|
return False
|
|
|
|
@classmethod
|
|
def revoked(cls, filter_, stix_obj):
|
|
return cls._boolean(filter_, stix_obj["revoked"])
|
|
|
|
@classmethod
|
|
def type(cls, filter_, stix_obj):
|
|
return cls._string(filter_, stix_obj["type"])
|