search_censys.py

''' 
Copyright 2023 The Board of Trustees of The Leland Stanford Junior University

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
'''


import sys
from censys.search import CensysCerts, CensysHosts
from datetime import date
from ipaddress import ip_address, IPv4Address, IPv6Address

def search_censys(asn: int, ipv: int = None):
    """
    Queries Censys for all exposed services (IP, port) for the specified ASN.

    Starlink ASN: 14593
    Oneweb ASN: 800

    :param asn: the autonomous system number
    :param ipv: (optional) specify 4 or 6 to filter for IP version 
    (default is no filter)
    :return: list of exposed ip/port
    """ 

    h = CensysHosts()
    c = CensysCerts()
    exposed_services = {
        'date': [],
        'asn': [],
        'ip': [],
        'port': [],
        'dns_name': [], 
        'pep_link': [],
    }

    # certs_queried = {}

    # search Censys for services matching asn
    for page in h.search("autonomous_system.asn:" + str(asn), pages=-1):
        for entry in page:
            try:
                for service in entry['services']:
                    # filter IPv if specified
                    if (((ipv == 4) and type(ip_address(entry['ip'])) is not IPv4Address) or 
                        ((ipv == 6) and type(ip_address(entry['ip'])) is not IPv6Address)):
                        continue

                    # get DNS name if it exists
                    dns_name = []
                    # FIXME
                    try: 
                        dns_name = entry['dns']['reverse_dns']['names']
                    except:
                        dns_name = []

                    # label hosts using pep-link 
                    # (commented out because costly in # of queries)
                    pep_link = None
                    # try:
                    #     # services.tls.certificates.leaf_data.subject_dn
                    #     certificate = service['certificate']
                    #     cert = ""
                    #     if certificate in certs_queried:
                    #         cert = certs_queried[certificate]
                    #     else:
                    #         cert = c.raw_search(certificate)
                    #         certs_queried[certificate] = cert
                    #         print(certificate)

                    #     subject_dn = cert['result']['hits'][0]['parsed']['subject_dn']
                    #     if 'peplink' in subject_dn.lower():
                    #         pep_link = True
                    # except:
                    #     pep_link = False

                    exposed_services['asn'].append(asn)
                    exposed_services['ip'].append(entry['ip'])
                    exposed_services['port'].append(service['port'])
                    exposed_services['dns_name'].append(dns_name)
                    exposed_services['pep_link'].append(pep_link) 

            except Exception as e:
                sys.stderr.write(str(e) + "\t could not get ip")
                sys.stderr.write(str(entry))

    exposed_services['date'] = [str(date.today())] * len(exposed_services['ip'])
    return exposed_services