import json import requests from . import check_input_attribute, standard_error_message from collections import defaultdict from pymisp import MISPEvent, MISPObject misperrors = {'error': 'Error'} mispattributes = {'input': ['vulnerability'], 'format': 'misp_standard'} moduleinfo = {'version': '1', 'author': 'Christian Studer', 'description': 'An expansion module to enrich a CVE attribute with the vulnerability information.', 'module-type': ['expansion', 'hover']} moduleconfig = ["custom_API"] cveapi_url = 'https://cve.circl.lu/api/cve/' class VulnerabilityParser(): def __init__(self, attribute, vulnerability, api_url): self.attribute = attribute self.vulnerability = vulnerability self.api_url = api_url self.misp_event = MISPEvent() self.misp_event.add_attribute(**attribute) self.references = defaultdict(list) self.capec_features = ('id', 'name', 'summary', 'prerequisites', 'solutions') self.vulnerability_mapping = { 'id': ('vulnerability', 'id'), 'summary': ('text', 'summary'), 'vulnerable_configuration': ('cpe', 'vulnerable_configuration'), 'vulnerable_configuration_cpe_2_2': ('cpe', 'vulnerable_configuration'), 'Modified': ('datetime', 'modified'), 'Published': ('datetime', 'published'), 'references': ('link', 'references'), 'cvss': ('float', 'cvss-score')} self.weakness_mapping = {'name': 'name', 'description_summary': 'description', 'status': 'status', 'weaknessabs': 'weakness-abs'} def get_result(self): if self.references: self.__build_references() event = json.loads(self.misp_event.to_json()) results = {key: event[key] for key in ('Attribute', 'Object') if (key in event and event[key])} return {'results': results} def parse_vulnerability_information(self): vulnerability_object = MISPObject('vulnerability') for feature in ('id', 'summary', 'Modified', 'cvss'): value = self.vulnerability.get(feature) if value: attribute_type, relation = self.vulnerability_mapping[feature] vulnerability_object.add_attribute(relation, **{'type': attribute_type, 'value': value}) if 'Published' in self.vulnerability: vulnerability_object.add_attribute('published', **{'type': 'datetime', 'value': self.vulnerability['Published']}) vulnerability_object.add_attribute('state', **{'type': 'text', 'value': 'Published'}) for feature in ('references', 'vulnerable_configuration', 'vulnerable_configuration_cpe_2_2'): if feature in self.vulnerability: attribute_type, relation = self.vulnerability_mapping[feature] for value in self.vulnerability[feature]: if isinstance(value, dict): value = value['title'] vulnerability_object.add_attribute(relation, **{'type': attribute_type, 'value': value}) vulnerability_object.add_reference(self.attribute['uuid'], 'related-to') self.misp_event.add_object(vulnerability_object) if 'cwe' in self.vulnerability and self.vulnerability['cwe'] not in ('Unknown', 'NVD-CWE-noinfo'): self.__parse_weakness(vulnerability_object.uuid) if 'capec' in self.vulnerability: self.__parse_capec(vulnerability_object.uuid) def __build_references(self): for object_uuid, references in self.references.items(): for misp_object in self.misp_event.objects: if misp_object.uuid == object_uuid: for reference in references: misp_object.add_reference(**reference) break def __parse_capec(self, vulnerability_uuid): for capec in self.vulnerability['capec']: capec_object = MISPObject('attack-pattern') for feature in self.capec_features: capec_object.add_attribute(feature, **{'type': 'text', 'value': capec[feature]}) for related_weakness in capec['related_weakness']: attribute = {'type': 'weakness', 'value': f"CWE-{related_weakness}"} capec_object.add_attribute('related-weakness', **attribute) self.misp_event.add_object(capec_object) self.references[vulnerability_uuid].append( { 'referenced_uuid': capec_object.uuid, 'relationship_type': 'targeted-by' } ) def __parse_weakness(self, vulnerability_uuid): cwe_string, cwe_id = self.vulnerability['cwe'].split('-') cwes = requests.get(self.api_url.replace('/cve/', '/cwe')) if cwes.status_code == 200: for cwe in cwes.json(): if cwe['id'] == cwe_id: weakness_object = MISPObject('weakness') weakness_object.add_attribute('id', {'type': 'weakness', 'value': f'{cwe_string}-{cwe_id}'}) for feature, relation in self.weakness_mapping.items(): if cwe.get(feature): weakness_object.add_attribute(relation, **{'type': 'text', 'value': cwe[feature]}) self.misp_event.add_object(weakness_object) self.references[vulnerability_uuid].append( { 'referenced_uuid': weakness_object.uuid, 'relationship_type': 'weakened-by' } ) break def check_url(url): return "{}/".format(url) if not url.endswith('/') else url def handler(q=False): if q is False: return False request = json.loads(q) if not request.get('attribute') or not check_input_attribute(request['attribute']): return {'error': f'{standard_error_message}, which should contain at least a type, a value and an uuid.'} attribute = request['attribute'] if attribute.get('type') != 'vulnerability': misperrors['error'] = 'Vulnerability id missing.' return misperrors api_url = check_url(request['config']['custom_API']) if request['config'].get('custom_API') else cveapi_url r = requests.get("{}{}".format(api_url, attribute['value'])) if r.status_code == 200: vulnerability = r.json() if not vulnerability: misperrors['error'] = 'Non existing CVE' return misperrors['error'] else: misperrors['error'] = 'API not accessible' return misperrors['error'] parser = VulnerabilityParser(attribute, vulnerability, api_url) parser.parse_vulnerability_information() return parser.get_result() def introspection(): return mispattributes def version(): moduleinfo['config'] = moduleconfig return moduleinfo