Modules for expansion services, import and export in MISP http://misp.github.io/misp-modules
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"""vt_graph_parser.helpers.rules.
This module provides rules that helps MISP importers to connect MISP attributes
between them using VirusTotal relationship. Check all available relationship
here:
- File: https://developers.virustotal.com/v3/reference/#files-relationships
- URL: https://developers.virustotal.com/v3/reference/#urls-relationships
- Domain: https://developers.virustotal.com/v3/reference/#domains-relationships
- IP: https://developers.virustotal.com/v3/reference/#ip-relationships
"""
import abc
class MispEventRule(object):
"""Rules for MISP event nodes connection object wrapper."""
def __init__(self, last_rule=None, node=None):
"""Create a MispEventRule instance.
MispEventRule is a collection of rules that can infer the relationships
between nodes from MISP events.
Args:
last_rule (MispEventRule): previous rule.
node (Node): actual node.
"""
self.last_rule = last_rule
self.node = node
self.relation_event = {
"ip_address": self.__ip_transition,
"url": self.__url_transition,
"domain": self.__domain_transition,
"file": self.__file_transition
}
def get_last_different_rule(self):
"""Search the last rule whose event was different from actual.
Returns:
MispEventRule: the last different rule.
"""
if not isinstance(self, self.last_rule.__class__):
return self.last_rule
else:
return self.last_rule.get_last_different_rule()
def resolve_relation(self, graph, node, misp_category):
"""Try to infer a relationship between two nodes.
This method is based on a non-deterministic finite automaton for
this reason the future rule only depends on the actual rule and the input
node.
For example if the actual rule is a MISPEventDomainRule and the given node
is an ip_address node, the connection type between them will be
`resolutions` and the this rule will transit to MISPEventIPRule.
Args:
graph (VTGraph): graph to be computed.
node (Node): the node to be linked.
misp_category: (str): MISP category of the given node.
Returns:
MispEventRule: the transited rule.
"""
if node.node_type in self.relation_event:
return self.relation_event[node.node_type](graph, node, misp_category)
else:
return self.manual_link(graph, node)
def manual_link(self, graph, node):
"""Creates a manual link between self.node and the given node.
We accept MISP types that VirusTotal does not know how to link, so we create
a end to end relationship instead of create an unknown relationship node.
Args:
graph (VTGraph): graph to be computed.
node (Node): the node to be linked.
Returns:
MispEventRule: the transited rule.
"""
graph.add_link(self.node.node_id, node.node_id, "manual")
return self
@abc.abstractmethod
def __file_transition(self, graph, node, misp_category):
"""Make a new transition due to file attribute event.
Args:
graph (VTGraph): graph to be computed.
node (Node): the node to be linked.
misp_category: (str): MISP category of the given node.
Returns:
MispEventRule: the transited rule.
"""
pass
@abc.abstractmethod
def __ip_transition(self, graph, node, misp_category):
"""Make a new transition due to ip attribute event.
Args:
graph (VTGraph): graph to be computed.
node (Node): the node to be linked.
misp_category: (str): MISP category of the given node.
Returns:
MispEventRule: the transited rule.
"""
pass
@abc.abstractmethod
def __url_transition(self, graph, node, misp_category):
"""Make a new transition due to url attribute event.
Args:
graph (VTGraph): graph to be computed.
node (Node): the node to be linked.
misp_category: (str): MISP category of the given node.
Returns:
MispEventRule: the transited rule.
"""
pass
@abc.abstractmethod
def __domain_transition(self, graph, node, misp_category):
"""Make a new transition due to domain attribute event.
Args:
graph (VTGraph): graph to be computed.
node (Node): the node to be linked.
misp_category: (str): MISP category of the given node.
Returns:
MispEventRule: the transited rule.
"""
pass
class MispEventURLRule(MispEventRule):
"""Rule for URL event."""
def __init__(self, last_rule=None, node=None):
super(MispEventURLRule, self).__init__(last_rule, node)
self.relation_event = {
"ip_address": self.__ip_transition,
"url": self.__url_transition,
"domain": self.__domain_transition,
"file": self.__file_transition
}
def __file_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "downloaded_files")
return MispEventFileRule(self, node)
def __ip_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "contacted_ips")
return MispEventIPRule(self, node)
def __url_transition(self, graph, node, misp_category):
suitable_rule = self.get_last_different_rule()
if not isinstance(suitable_rule, MispEventInitialRule):
return suitable_rule.resolve_relation(graph, node, misp_category)
else:
return MispEventURLRule(self, node)
def __domain_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "contacted_domains")
return MispEventDomainRule(self, node)
class MispEventIPRule(MispEventRule):
"""Rule for IP event."""
def __init__(self, last_rule=None, node=None):
super(MispEventIPRule, self).__init__(last_rule, node)
self.relation_event = {
"ip_address": self.__ip_transition,
"url": self.__url_transition,
"domain": self.__domain_transition,
"file": self.__file_transition
}
def __file_transition(self, graph, node, misp_category):
connection_type = "communicating_files"
if misp_category == "Artifacts dropped":
connection_type = "downloaded_files"
graph.add_link(self.node.node_id, node.node_id, connection_type)
return MispEventFileRule(self, node)
def __ip_transition(self, graph, node, misp_category):
suitable_rule = self.get_last_different_rule()
if not isinstance(suitable_rule, MispEventInitialRule):
return suitable_rule.resolve_relation(graph, node, misp_category)
else:
return MispEventIPRule(self, node)
def __url_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "urls")
return MispEventURLRule(self, node)
def __domain_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "resolutions")
return MispEventDomainRule(self, node)
class MispEventDomainRule(MispEventRule):
"""Rule for domain event."""
def __init__(self, last_rule=None, node=None):
super(MispEventDomainRule, self).__init__(last_rule, node)
self.relation_event = {
"ip_address": self.__ip_transition,
"url": self.__url_transition,
"domain": self.__domain_transition,
"file": self.__file_transition
}
def __file_transition(self, graph, node, misp_category):
connection_type = "communicating_files"
if misp_category == "Artifacts dropped":
connection_type = "downloaded_files"
graph.add_link(self.node.node_id, node.node_id, connection_type)
return MispEventFileRule(self, node)
def __ip_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "resolutions")
return MispEventIPRule(self, node)
def __url_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "urls")
return MispEventURLRule(self, node)
def __domain_transition(self, graph, node, misp_category):
suitable_rule = self.get_last_different_rule()
if not isinstance(suitable_rule, MispEventInitialRule):
return suitable_rule.resolve_relation(graph, node, misp_category)
else:
graph.add_link(self.node.node_id, node.node_id, "siblings")
return MispEventDomainRule(self, node)
class MispEventFileRule(MispEventRule):
"""Rule for File event."""
def __init__(self, last_rule=None, node=None):
super(MispEventFileRule, self).__init__(last_rule, node)
self.relation_event = {
"ip_address": self.__ip_transition,
"url": self.__url_transition,
"domain": self.__domain_transition,
"file": self.__file_transition
}
def __file_transition(self, graph, node, misp_category):
suitable_rule = self.get_last_different_rule()
if not isinstance(suitable_rule, MispEventInitialRule):
return suitable_rule.resolve_relation(graph, node, misp_category)
else:
return MispEventFileRule(self, node)
def __ip_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "contacted_ips")
return MispEventIPRule(self, node)
def __url_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "contacted_urls")
return MispEventURLRule(self, node)
def __domain_transition(self, graph, node, misp_category):
graph.add_link(self.node.node_id, node.node_id, "contacted_domains")
return MispEventDomainRule(self, node)
class MispEventInitialRule(MispEventRule):
"""Initial rule."""
def __init__(self, last_rule=None, node=None):
super(MispEventInitialRule, self).__init__(last_rule, node)
self.relation_event = {
"ip_address": self.__ip_transition,
"url": self.__url_transition,
"domain": self.__domain_transition,
"file": self.__file_transition
}
def __file_transition(self, graph, node, misp_category):
return MispEventFileRule(self, node)
def __ip_transition(self, graph, node, misp_category):
return MispEventIPRule(self, node)
def __url_transition(self, graph, node, misp_category):
return MispEventURLRule(self, node)
def __domain_transition(self, graph, node, misp_category):
return MispEventDomainRule(self, node)