misp-modules/misp_modules/modules/expansion/cve_advanced.py

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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)
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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')}
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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)
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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):
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cwe_string, cwe_id = self.vulnerability['cwe'].split('-')
cwes = requests.get(self.api_url.replace('/cve/', '/cwe'))
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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}'})
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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'
}
)
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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