From ba8e4767d03ac8ecc06536b750399221d7153307 Mon Sep 17 00:00:00 2001 From: Matt Weber Date: Sun, 31 Jan 2021 14:38:15 +0100 Subject: [PATCH] support/scripts/cpedb.py: new CPE XML helper MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Python class which consumes a NIST CPE XML and provides helper functions to access and search the db's data. - Defines the CPE as a object with operations / formats - Processing of CPE dictionary Signed-off-by: Matthew Weber Co-Developed-by: Grégory Clement Co-Developed-by: Thomas Petazzoni Signed-off-by: Thomas Petazzoni Signed-off-by: Arnout Vandecappelle (Essensium/Mind) --- support/scripts/cpedb.py | 203 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 support/scripts/cpedb.py diff --git a/support/scripts/cpedb.py b/support/scripts/cpedb.py new file mode 100644 index 0000000000..825ed6cb1e --- /dev/null +++ b/support/scripts/cpedb.py @@ -0,0 +1,203 @@ +#!/usr/bin/env python3 + +import xml.etree.ElementTree as ET +from xml.etree.ElementTree import Element, SubElement +import gzip +import os +import pickle +import requests +import time +from xml.dom import minidom + +VALID_REFS = ['VENDOR', 'VERSION', 'CHANGE_LOG', 'PRODUCT', 'PROJECT', 'ADVISORY'] + +CPEDB_URL = "https://static.nvd.nist.gov/feeds/xml/cpe/dictionary/official-cpe-dictionary_v2.3.xml.gz" + +ns = { + '': 'http://cpe.mitre.org/dictionary/2.0', + 'cpe-23': 'http://scap.nist.gov/schema/cpe-extension/2.3', + 'xml': 'http://www.w3.org/XML/1998/namespace' +} + + +class CPE: + def __init__(self, cpe_str, titles, refs): + self.cpe_str = cpe_str + self.titles = titles + self.references = refs + self.cpe_cur_ver = "".join(self.cpe_str.split(":")[5:6]) + + def update_xml_dict(self): + ET.register_namespace('', 'http://cpe.mitre.org/dictionary/2.0') + cpes = Element('cpe-list') + cpes.set('xmlns:cpe-23', "http://scap.nist.gov/schema/cpe-extension/2.3") + cpes.set('xmlns:ns6', "http://scap.nist.gov/schema/scap-core/0.1") + cpes.set('xmlns:scap-core', "http://scap.nist.gov/schema/scap-core/0.3") + cpes.set('xmlns:config', "http://scap.nist.gov/schema/configuration/0.1") + cpes.set('xmlns:xsi', "http://www.w3.org/2001/XMLSchema-instance") + cpes.set('xmlns:meta', "http://scap.nist.gov/schema/cpe-dictionary-metadata/0.2") + cpes.set('xsi:schemaLocation', " ".join(["http://scap.nist.gov/schema/cpe-extension/2.3", + "https://scap.nist.gov/schema/cpe/2.3/cpe-dictionary-extension_2.3.xsd", + "http://cpe.mitre.org/dictionary/2.0", + "https://scap.nist.gov/schema/cpe/2.3/cpe-dictionary_2.3.xsd", + "http://scap.nist.gov/schema/cpe-dictionary-metadata/0.2", + "https://scap.nist.gov/schema/cpe/2.1/cpe-dictionary-metadata_0.2.xsd", + "http://scap.nist.gov/schema/scap-core/0.3", + "https://scap.nist.gov/schema/nvd/scap-core_0.3.xsd", + "http://scap.nist.gov/schema/configuration/0.1", + "https://scap.nist.gov/schema/nvd/configuration_0.1.xsd", + "http://scap.nist.gov/schema/scap-core/0.1", + "https://scap.nist.gov/schema/nvd/scap-core_0.1.xsd"])) + item = SubElement(cpes, 'cpe-item') + cpe_short_name = CPE.short_name(self.cpe_str) + cpe_new_ver = CPE.version_update(self.cpe_str) + + item.set('name', 'cpe:/' + cpe_short_name) + self.titles[0].text.replace(self.cpe_cur_ver, cpe_new_ver) + for title in self.titles: + item.append(title) + if self.references: + item.append(self.references) + cpe23item = SubElement(item, 'cpe-23:cpe23-item') + cpe23item.set('name', self.cpe_str) + + # Generate the XML as a string + xmlstr = ET.tostring(cpes) + + # And use minidom to pretty print the XML + return minidom.parseString(xmlstr).toprettyxml(encoding="utf-8").decode("utf-8") + + @staticmethod + def version(cpe): + return cpe.split(":")[5] + + @staticmethod + def product(cpe): + return cpe.split(":")[4] + + @staticmethod + def short_name(cpe): + return ":".join(cpe.split(":")[2:6]) + + @staticmethod + def version_update(cpe): + return ":".join(cpe.split(":")[5:6]) + + @staticmethod + def no_version(cpe): + return ":".join(cpe.split(":")[:5]) + + +class CPEDB: + def __init__(self, nvd_path): + self.all_cpes = dict() + self.all_cpes_no_version = dict() + self.nvd_path = nvd_path + + def gen_cached_cpedb(self, cpedb, cache_all_cpes, cache_all_cpes_no_version): + print("CPE: Unzipping xml manifest...") + nist_cpe_file = gzip.GzipFile(fileobj=open(cpedb, 'rb')) + print("CPE: Converting xml manifest to dict...") + tree = ET.parse(nist_cpe_file) + all_cpedb = tree.getroot() + self.parse_dict(all_cpedb) + + print("CPE: Caching dictionary") + cpes_file = open(cache_all_cpes, 'wb') + pickle.dump(self.all_cpes, cpes_file) + cpes_file.close() + cpes_file = open(cache_all_cpes_no_version, 'wb') + pickle.dump(self.all_cpes_no_version, cpes_file) + cpes_file.close() + + def get_xml_dict(self): + print("CPE: Setting up NIST dictionary") + if not os.path.exists(os.path.join(self.nvd_path, "cpe")): + os.makedirs(os.path.join(self.nvd_path, "cpe")) + + cpe_dict_local = os.path.join(self.nvd_path, "cpe", os.path.basename(CPEDB_URL)) + if not os.path.exists(cpe_dict_local) or os.stat(cpe_dict_local).st_mtime < time.time() - 86400: + print("CPE: Fetching xml manifest from [" + CPEDB_URL + "]") + cpe_dict = requests.get(CPEDB_URL) + open(cpe_dict_local, "wb").write(cpe_dict.content) + + cache_all_cpes = os.path.join(self.nvd_path, "cpe", "all_cpes.pkl") + cache_all_cpes_no_version = os.path.join(self.nvd_path, "cpe", "all_cpes_no_version.pkl") + + if not os.path.exists(cache_all_cpes) or \ + not os.path.exists(cache_all_cpes_no_version) or \ + os.stat(cache_all_cpes).st_mtime < os.stat(cpe_dict_local).st_mtime or \ + os.stat(cache_all_cpes_no_version).st_mtime < os.stat(cpe_dict_local).st_mtime: + self.gen_cached_cpedb(cpe_dict_local, + cache_all_cpes, + cache_all_cpes_no_version) + + print("CPE: Loading CACHED dictionary") + cpe_file = open(cache_all_cpes, 'rb') + self.all_cpes = pickle.load(cpe_file) + cpe_file.close() + cpe_file = open(cache_all_cpes_no_version, 'rb') + self.all_cpes_no_version = pickle.load(cpe_file) + cpe_file.close() + + def parse_dict(self, all_cpedb): + # Cycle through the dict and build two dict to be used for custom + # lookups of partial and complete CPE objects + # The objects are then used to create new proposed XML updates if + # if is determined one is required + # Out of the different language titles, select English + for cpe in all_cpedb.findall(".//{http://cpe.mitre.org/dictionary/2.0}cpe-item"): + cpe_titles = [] + for title in cpe.findall('.//{http://cpe.mitre.org/dictionary/2.0}title[@xml:lang="en-US"]', ns): + title.tail = None + cpe_titles.append(title) + + # Some older CPE don't include references, if they do, make + # sure we handle the case of one ref needing to be packed + # in a list + cpe_ref = cpe.find(".//{http://cpe.mitre.org/dictionary/2.0}references") + if cpe_ref: + for ref in cpe_ref.findall(".//{http://cpe.mitre.org/dictionary/2.0}reference"): + ref.tail = None + ref.text = ref.text.upper() + if ref.text not in VALID_REFS: + ref.text = ref.text + "-- UPDATE this entry, here are some examples and just one word should be used -- " + ' '.join(VALID_REFS) # noqa E501 + cpe_ref.tail = None + cpe_ref.text = None + + cpe_str = cpe.find(".//{http://scap.nist.gov/schema/cpe-extension/2.3}cpe23-item").get('name') + item = CPE(cpe_str, cpe_titles, cpe_ref) + cpe_str_no_version = CPE.no_version(cpe_str) + # This dict must have a unique key for every CPE version + # which allows matching to the specific obj data of that + # NIST dict entry + self.all_cpes.update({cpe_str: item}) + # This dict has one entry for every CPE (w/o version) to allow + # partial match (no valid version) check (the obj is saved and + # used as seed for suggested xml updates. By updating the same + # non-version'd entry, it assumes the last update here is the + # latest version in the NIST dict) + self.all_cpes_no_version.update({cpe_str_no_version: item}) + + def find_partial(self, cpe_str): + cpe_str_no_version = CPE.no_version(cpe_str) + if cpe_str_no_version in self.all_cpes_no_version: + return cpe_str_no_version + + def find_partial_obj(self, cpe_str): + cpe_str_no_version = CPE.no_version(cpe_str) + if cpe_str_no_version in self.all_cpes_no_version: + return self.all_cpes_no_version[cpe_str_no_version] + + def find_partial_latest_version(self, cpe_str_partial): + cpe_obj = self.find_partial_obj(cpe_str_partial) + return cpe_obj.cpe_cur_ver + + def find(self, cpe_str): + if self.find_partial(cpe_str): + if cpe_str in self.all_cpes: + return cpe_str + + def gen_update_xml(self, cpe_str): + cpe = self.find_partial_obj(cpe_str) + return cpe.update_xml_dict()