#!/usr/bin/env python # -*- coding: utf-8 -*- """ The MIT License (MIT) Copyright (C) 2015 Andris Raugulis (moo@arthepsy.eu) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. """ from __future__ import print_function import os, io, sys, socket, struct SSH_BANNER = 'SSH-2.0-OpenSSH_7.1' SOCK_CONN_TIMEOUT = 3.0 SOCK_READ_TIMEOUT = 5.0 def usage(): p = os.path.basename(sys.argv[0]) out.head('# {0} v1.0.20151223, moo@arthepsy.eu'.format(p)) out.info('\nusage: {} [-nv] host[:port]\n'.format(p)) out.info(' -v verbose') out.info(' -n disable colors' + os.linesep) sys.exit(1) class Output(object): colors = True verbose = False _colors = { 'head': 36, 'good': 32, 'fail': 31, 'warn': 33, } def sep(self): print() def _colorized(self, color): return lambda x: print(color + x + '\033[0m') def __getattr__(self, name): if self.colors and os.name == 'posix' and name in self._colors: color = '\033[0;{0}m'.format(self._colors[name]) return self._colorized(color) else: return lambda x: print(x) class KexParty(object): encryption = [] mac = [] compression = [] languages = [] class Kex(object): cookie = None kex_algorithms = [] key_algorithms = [] server = KexParty() client = KexParty() follows = False unused = 0 @classmethod def parse(cls, payload): kex = cls() buf = ReadBuf(payload) kex.cookie = buf.read_raw(16) kex.kex_algorithms = buf.read_list() kex.key_algorithms = buf.read_list() kex.client.encryption = buf.read_list() kex.server.encryption = buf.read_list() kex.client.mac = buf.read_list() kex.server.mac = buf.read_list() kex.client.compression = buf.read_list() kex.server.compression = buf.read_list() kex.client.languages = buf.read_list() kex.server.languages = buf.read_list() kex.follows = buf.read_bool() kex.unused = buf.read_int() return kex class ReadBuf(object): def __init__(self, data = None): self._buf = io.BytesIO(data) if data else io.BytesIO() self._len = len(data) if data else 0 @property def unread_len(self): return self._len - self._buf.tell() def read_raw(self, size): return self._buf.read(size) def read_line(self): return self._buf.readline().rstrip().decode('utf-8') def read_int(self): return struct.unpack('>I', self._buf.read(4))[0] def read_bool(self): return struct.unpack('b', self._buf.read(1))[0] != 0 def read_list(self): list_size = self.read_int() return self._buf.read(list_size).decode().split(',') class SockBuf(ReadBuf): def __init__(self, s): super(SockBuf, self).__init__() self.__sock = s def recv(self, size = 2048): data = self.__sock.recv(size) pos = self._buf.tell() self._buf.seek(0, 2) self._buf.write(data) self._len += len(data) self._buf.seek(pos, 0) def get_ssh_ver(versions): tv = [] for v in versions.split(','): if v.startswith('d'): tv.append('Dropbear SSH {0}'.format(v[1:])) else: tv.append('OpenSSH {0}'.format(v)) return 'available since ' + ', '.join(tv).rstrip(', ') WARN_OPENSSH72_LEGACY = 'removed (in client) since OpenSSH 7.2, legacy algorithm' WARN_OPENSSH70_LEGACY = 'removed since OpenSSH 7.0, legacy algorithm' FAIL_OPENSSH70_WEAK = 'removed (in server) and disabled (in client) since OpenSSH 7.0, weak algorithm' FAIL_OPENSSH70_LOGJAM = 'disabled (in client) since OpenSSH 7.0, logjam attack' INFO_OPENSSH69_CHACHA = 'default cipher since OpenSSH 6.9.' FAIL_OPENSSH67_UNSAFE = 'removed (in server) since OpenSSH 6.7, unsafe algorithm' FAIL_OPENSSH61_REMOVE = 'removed since OpenSSH 6.1, removed from specification' FAIL_OPENSSH31_REMOVE = 'removed since OpenSSH 3.1' FAIL_DBEAR67_DISABLED = 'disabled since Dropbear SSH 2015.67' FAIL_DBEAR53_DISABLED = 'disabled since Dropbear SSH 0.53' KEX_DB = { 'kex': { 'diffie-hellman-group1-sha1': ['2.3.0,d0.28', [FAIL_OPENSSH67_UNSAFE, FAIL_OPENSSH70_LOGJAM]], 'diffie-hellman-group14-sha1': ['3.9,d0.53'], 'diffie-hellman-group-exchange-sha1': ['2.3.0', [FAIL_OPENSSH67_UNSAFE]], 'diffie-hellman-group-exchange-sha256': ['4.4'], 'ecdh-sha2-nistp256': ['5.7,d2013.62'], 'ecdh-sha2-nistp384': ['5.7,d2013.62'], 'ecdh-sha2-nistp521': ['5.7,d2013.62'], 'curve25519-sha256@libssh.org': ['6.5,d2013.62'], 'kexguess2@matt.ucc.asn.au': ['d2013.57'], }, 'key': { 'ssh-ed25519': ['6.5'], 'ssh-ed25519-cert-v01@openssh.com': ['6.5'], 'ssh-rsa': ['2.5.0,d0.28'], 'ssh-dss': ['2.1.0,d0.28', [FAIL_OPENSSH70_WEAK]], 'ecdsa-sha2-nistp256': ['5.7,d2013.62'], 'ecdsa-sha2-nistp384': ['5.7,d2013.62'], 'ecdsa-sha2-nistp521': ['5.7,d2013.62'], 'ssh-rsa-cert-v00@openssh.com': ['5.4', [], [WARN_OPENSSH70_LEGACY]], 'ssh-dss-cert-v00@openssh.com': ['5.4', [FAIL_OPENSSH70_WEAK], [WARN_OPENSSH70_LEGACY]], 'ssh-rsa-cert-v01@openssh.com': ['5.6'], 'ssh-dss-cert-v01@openssh.com': ['5.6', [FAIL_OPENSSH70_WEAK]], 'ecdsa-sha2-nistp256-cert-v01@openssh.com': ['5.7'], 'ecdsa-sha2-nistp384-cert-v01@openssh.com': ['5.7'], 'ecdsa-sha2-nistp521-cert-v01@openssh.com': ['5.7'], }, 'enc': { '3des-cbc': ['1.2.2,d0.28', [FAIL_OPENSSH67_UNSAFE]], '3des-ctr': ['d0.52'], 'blowfish-cbc': ['1.2.2,d0.28', [FAIL_OPENSSH67_UNSAFE, FAIL_DBEAR53_DISABLED], [WARN_OPENSSH72_LEGACY]], 'twofish-cbc': ['d0.28', [FAIL_DBEAR67_DISABLED]], 'twofish128-cbc': ['d0.47', [FAIL_DBEAR67_DISABLED]], 'twofish256-cbc': ['d0.47', [FAIL_DBEAR67_DISABLED]], 'twofish128-ctr': ['d2015.68'], 'twofish256-ctr': ['d2015.68'], 'cast128-cbc': ['2.1.0', [FAIL_OPENSSH67_UNSAFE], [WARN_OPENSSH72_LEGACY]], 'arcfour': ['2.1.0', [FAIL_OPENSSH67_UNSAFE], [WARN_OPENSSH72_LEGACY]], 'arcfour128': ['4.2', [FAIL_OPENSSH67_UNSAFE], [WARN_OPENSSH72_LEGACY]], 'arcfour256': ['4.2', [FAIL_OPENSSH67_UNSAFE], [WARN_OPENSSH72_LEGACY]], 'aes128-cbc': ['2.3.0,d0.28', [FAIL_OPENSSH67_UNSAFE]], 'aes192-cbc': ['2.3.0', [FAIL_OPENSSH67_UNSAFE]], 'aes256-cbc': ['2.3.0,d0.47', [FAIL_OPENSSH67_UNSAFE]], 'rijndael128-cbc': ['2.3.0', [FAIL_OPENSSH31_REMOVE]], 'rijndael192-cbc': ['2.3.0', [FAIL_OPENSSH31_REMOVE]], 'rijndael256-cbc': ['2.3.0', [FAIL_OPENSSH31_REMOVE]], 'rijndael-cbc@lysator.liu.se': ['2.3.0', [], [WARN_OPENSSH72_LEGACY]], 'aes128-ctr': ['3.7,d0.52'], 'aes192-ctr': ['3.7'], 'aes256-ctr': ['3.7,d0.52'], 'aes128-gcm@openssh.com': ['6.2'], 'aes256-gcm@openssh.com': ['6.2'], 'chacha20-poly1305@openssh.com': ['6.5', [], [], [INFO_OPENSSH69_CHACHA]], }, 'mac': { 'hmac-sha1': ['2.1.0,d0.28'], 'hmac-sha1-96': ['2.5.0,d0.47', [FAIL_OPENSSH67_UNSAFE]], 'hmac-sha2-256': ['5.9,d2013.56'], 'hmac-sha2-256-96': ['5.9', [FAIL_OPENSSH61_REMOVE]], 'hmac-sha2-512': ['5.9,d2013.56'], 'hmac-sha2-512-96': ['5.9', [FAIL_OPENSSH61_REMOVE]], 'hmac-md5': ['2.1.0,d0.28', [FAIL_OPENSSH67_UNSAFE], [WARN_OPENSSH72_LEGACY]], 'hmac-md5-96': ['2.5.0', [FAIL_OPENSSH67_UNSAFE], [WARN_OPENSSH72_LEGACY]], 'hmac-ripemd160': ['2.5.0', [FAIL_OPENSSH67_UNSAFE]], 'hmac-ripemd160@openssh.com': ['2.1.0', [FAIL_OPENSSH67_UNSAFE]], 'umac-64@openssh.com': ['4.7'], 'umac-128@openssh.com': ['6.2'], 'hmac-sha1-etm@openssh.com': ['6.2'], 'hmac-sha1-96-etm@openssh.com': ['6.2', [FAIL_OPENSSH67_UNSAFE]], 'hmac-sha2-256-etm@openssh.com': ['6.2'], 'hmac-sha2-512-etm@openssh.com': ['6.2'], 'hmac-md5-etm@openssh.com': ['6.2', [FAIL_OPENSSH67_UNSAFE], [WARN_OPENSSH72_LEGACY]], 'hmac-md5-96-etm@openssh.com': ['6.2', [FAIL_OPENSSH67_UNSAFE], [WARN_OPENSSH72_LEGACY]], 'hmac-ripemd160-etm@openssh.com': ['6.2', [FAIL_OPENSSH67_UNSAFE]], 'umac-64-etm@openssh.com': ['6.2'], 'umac-128-etm@openssh.com': ['6.2'], } } def process_algorithms(alg_type, algorithms, maxlen=0): for algorithm in algorithms: process_algorithm(alg_type, algorithm, maxlen) def process_algorithm(alg_type, alg_name, alg_max_len=0): prefix = '(' + alg_type + ') ' if alg_max_len == 0: alg_max_len = len(alg_name) padding = ' ' * (alg_max_len - len(alg_name)) texts = [] if alg_name in KEX_DB[alg_type]: alg_desc = KEX_DB[alg_type][alg_name] ldesc = len(alg_desc) for idx, level in enumerate(['fail', 'warn', 'info']): if level == 'info': texts.append((level, get_ssh_ver(alg_desc[0]))) idx = idx + 1 if ldesc > idx: for t in alg_desc[idx]: texts.append((level, t)) if len(texts) == 0: texts.append(('info', '')) else: texts.append(('warn', 'unknown algorithm')) first = True for (level, text) in texts: f = getattr(out, level) text = '[' + level + '] ' + text if first: if first and level == 'info': f = out.good f(prefix + alg_name + padding + ' -- ' + text) first = False else: if out.verbose: f(prefix + alg_name + padding + ' -- ' + text) else: f(' ' * len(prefix + alg_name) + padding + ' `- ' + text) def process_kex(kex): state = 'zlib@openssh.com' in kex.server.compression state = 'enabled' if state else 'disabled' out.good('[info] compression is ' + state) ml = lambda l: max(len(i) for i in l) maxlen = max(ml(kex.kex_algorithms), ml(kex.key_algorithms), ml(kex.server.encryption), ml(kex.server.mac)) out.head('\n# key exchange algorithms') process_algorithms('kex', kex.kex_algorithms, maxlen) out.head('\n# host-key algorithms') process_algorithms('key', kex.key_algorithms, maxlen) out.head('\n# encryption algorithms (ciphers)') process_algorithms('enc', kex.server.encryption, maxlen) out.head('\n# message authentication code algorithms') process_algorithms('mac', kex.server.mac, maxlen) out.sep() def read_ssh_packet(sbuf): block_size = 8 header = sbuf.read_raw(block_size) packet_size = struct.unpack('>I', header[:4])[0] rest = header[4:] lrest = len(rest) padding = ord(rest[0:1]) packet_type = ord(rest[1:2]) if (packet_size - lrest) % block_size != 0: out.fail('[exception] invalid ssh packet (block size)') sys.exit(1) buf = sbuf.read_raw(packet_size - lrest) packet = rest[2:] + buf[0:packet_size - lrest] payload = packet[0:packet_size - padding] return packet_type, payload def parse_int(v): try: return int(v) except: return 0 def parse_args(): host = None port = 22 for arg in sys.argv[1:]: if arg.startswith('-'): arg = arg.lstrip('-') if arg == 'n': out.colors = False elif arg == 'v': out.verbose = True continue s = arg.split(':') host = s[0].strip() if len(s) > 1: port = parse_int(s[1]) if not host or port <= 0: usage() return host, port def main(): host, port = parse_args() s = None try: s = socket.create_connection((host, port), SOCK_CONN_TIMEOUT) s.settimeout(SOCK_READ_TIMEOUT) sbuf = SockBuf(s) s.send(SSH_BANNER.encode() + b'\r\n') sbuf.recv() banner = sbuf.read_line() out.head('# general') out.good('[info] banner: ' + banner) if banner.startswith('SSH-1.99-'): out.fail('[fail] protocol SSH1 enabled') if sbuf.unread_len == 0: sbuf.recv() packet_type, payload = read_ssh_packet(sbuf) if packet_type != 20: out.fail('[exception] did not receive MSG_KEXINIT (20), instead received unknown message ({0})'.format(packet_type)) sys.exit(1) kex = Kex.parse(payload) process_kex(kex) except Exception as e: out.fail('[fail] {}'.format(e)) sys.exit(1) finally: if s: s.close() if __name__ == '__main__': out = Output() main()