Git
/
ssh-audit
mirror of https://github.com/jtesta/ssh-audit.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
ssh-audit/src/ssh_audit/ssh_audit.py

996 lines
42 KiB
Python
Executable File
Raw Blame History

#!/usr/bin/env python3
"""
The MIT License (MIT)
Copyright (C) 2017-2020 Joe Testa (jtesta@positronsecurity.com)
Copyright (C) 2017 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.
"""
import getopt
import json
import os
import sys
import traceback
# pylint: disable=unused-import
from typing import Dict, List, Set, Sequence, Tuple, Iterable # noqa: F401
from typing import Callable, Optional, Union, Any # noqa: F401
from ssh_audit.globals import GITHUB_ISSUES_URL, VERSION
from ssh_audit.algorithm import Algorithm
from ssh_audit.algorithms import Algorithms
from ssh_audit.auditconf import AuditConf
from ssh_audit.banner import Banner
from ssh_audit import exitcodes
from ssh_audit.fingerprint import Fingerprint
from ssh_audit.gextest import GEXTest
from ssh_audit.hostkeytest import HostKeyTest
from ssh_audit.output import Output
from ssh_audit.outputbuffer import OutputBuffer
from ssh_audit.policy import Policy
from ssh_audit.product import Product
from ssh_audit.protocol import Protocol
from ssh_audit.software import Software
from ssh_audit.ssh1_kexdb import SSH1_KexDB
from ssh_audit.ssh1_publickeymessage import SSH1_PublicKeyMessage
from ssh_audit.ssh2_kex import SSH2_Kex
from ssh_audit.ssh2_kexdb import SSH2_KexDB
from ssh_audit.ssh_socket import SSH_Socket
from ssh_audit.utils import Utils
from ssh_audit.versionvulnerabilitydb import VersionVulnerabilityDB
try: # pragma: nocover
from colorama import init as colorama_init
colorama_init(strip=False) # pragma: nocover
except ImportError: # pragma: nocover
pass
def usage(err: Optional[str] = None) -> None:
retval = exitcodes.GOOD
uout = Output()
p = os.path.basename(sys.argv[0])
uout.head('# {} {}, https://github.com/jtesta/ssh-audit\n'.format(p, VERSION))
if err is not None and len(err) > 0:
uout.fail('\n' + err)
retval = exitcodes.UNKNOWN_ERROR
uout.info('usage: {0} [options] <host>\n'.format(p))
uout.info(' -h, --help print this help')
uout.info(' -1, --ssh1 force ssh version 1 only')
uout.info(' -2, --ssh2 force ssh version 2 only')
uout.info(' -4, --ipv4 enable IPv4 (order of precedence)')
uout.info(' -6, --ipv6 enable IPv6 (order of precedence)')
uout.info(' -b, --batch batch output')
uout.info(' -c, --client-audit starts a server on port 2222 to audit client\n software config (use -p to change port;\n use -t to change timeout)')
uout.info(' -j, --json JSON output')
uout.info(' -l, --level=<level> minimum output level (info|warn|fail)')
uout.info(' -L, --list-policies list all the official, built-in policies')
uout.info(' --lookup=<alg1,alg2,...> looks up an algorithm(s) without\n connecting to a server')
uout.info(' -M, --make-policy=<policy.txt> creates a policy based on the target server\n (i.e.: the target server has the ideal\n configuration that other servers should\n adhere to)')
uout.info(' -n, --no-colors disable colors')
uout.info(' -p, --port=<port> port to connect')
uout.info(' -P, --policy=<policy.txt> run a policy test using the specified policy')
uout.info(' -t, --timeout=<secs> timeout (in seconds) for connection and reading\n (default: 5)')
uout.info(' -T, --targets=<hosts.txt> a file containing a list of target hosts (one\n per line, format HOST[:PORT])')
uout.info(' -v, --verbose verbose output')
uout.sep()
sys.exit(retval)
def output_algorithms(title: str, alg_db: Dict[str, Dict[str, List[List[Optional[str]]]]], alg_type: str, algorithms: List[str], unknown_algs: List[str], is_json_output: bool, program_retval: int, maxlen: int = 0, alg_sizes: Optional[Dict[str, Tuple[int, int]]] = None) -> int: # pylint: disable=too-many-arguments
with OutputBuffer() as obuf:
for algorithm in algorithms:
program_retval = output_algorithm(alg_db, alg_type, algorithm, unknown_algs, program_retval, maxlen, alg_sizes)
if len(obuf) > 0 and not is_json_output:
out.head('# ' + title)
obuf.flush()
out.sep()
return program_retval
def output_algorithm(alg_db: Dict[str, Dict[str, List[List[Optional[str]]]]], alg_type: str, alg_name: str, unknown_algs: List[str], program_retval: int, alg_max_len: int = 0, alg_sizes: Optional[Dict[str, Tuple[int, int]]] = None) -> int:
prefix = '(' + alg_type + ') '
if alg_max_len == 0:
alg_max_len = len(alg_name)
padding = '' if out.batch else ' ' * (alg_max_len - len(alg_name))
# If this is an RSA host key or DH GEX, append the size to its name and fix
# the padding.
alg_name_with_size = None
if (alg_sizes is not None) and (alg_name in alg_sizes):
hostkey_size, ca_size = alg_sizes[alg_name]
if ca_size > 0:
alg_name_with_size = '%s (%d-bit cert/%d-bit CA)' % (alg_name, hostkey_size, ca_size)
padding = padding[0:-15]
else:
alg_name_with_size = '%s (%d-bit)' % (alg_name, hostkey_size)
padding = padding[0:-11]
texts = []
if len(alg_name.strip()) == 0:
return program_retval
alg_name_native = Utils.to_text(alg_name)
if alg_name_native in alg_db[alg_type]:
alg_desc = alg_db[alg_type][alg_name_native]
ldesc = len(alg_desc)
for idx, level in enumerate(['fail', 'warn', 'info']):
if level == 'info':
versions = alg_desc[0]
since_text = Algorithm.get_since_text(versions)
if since_text is not None and len(since_text) > 0:
texts.append((level, since_text))
idx = idx + 1
if ldesc > idx:
for t in alg_desc[idx]:
if t is None:
continue
texts.append((level, t))
if len(texts) == 0:
texts.append(('info', ''))
else:
texts.append(('warn', 'unknown algorithm'))
unknown_algs.append(alg_name)
alg_name = alg_name_with_size if alg_name_with_size is not None else alg_name
first = True
for level, text in texts:
if level == 'fail':
program_retval = exitcodes.FAILURE
elif level == 'warn' and program_retval != exitcodes.FAILURE: # If a failure was found previously, don't downgrade to warning.
program_retval = exitcodes.WARNING
f = getattr(out, level)
comment = (padding + ' -- [' + level + '] ' + text) if text != '' else ''
if first:
if first and level == 'info':
f = out.good
f(prefix + alg_name + comment)
first = False
else: # pylint: disable=else-if-used
if out.verbose:
f(prefix + alg_name + comment)
elif text != '':
comment = (padding + ' `- [' + level + '] ' + text)
f(' ' * len(prefix + alg_name) + comment)
return program_retval
def output_compatibility(algs: Algorithms, client_audit: bool, for_server: bool = True) -> None:
# Don't output any compatibility info if we're doing a client audit.
if client_audit:
return
ssh_timeframe = algs.get_ssh_timeframe(for_server)
comp_text = []
for ssh_prod in [Product.OpenSSH, Product.DropbearSSH]:
if ssh_prod not in ssh_timeframe:
continue
v_from = ssh_timeframe.get_from(ssh_prod, for_server)
v_till = ssh_timeframe.get_till(ssh_prod, for_server)
if v_from is None:
continue
if v_till is None:
comp_text.append('{} {}+'.format(ssh_prod, v_from))
elif v_from == v_till:
comp_text.append('{} {}'.format(ssh_prod, v_from))
else:
software = Software(None, ssh_prod, v_from, None, None)
if software.compare_version(v_till) > 0:
tfmt = '{0} {1}+ (some functionality from {2})'
else:
tfmt = '{0} {1}-{2}'
comp_text.append(tfmt.format(ssh_prod, v_from, v_till))
if len(comp_text) > 0:
out.good('(gen) compatibility: ' + ', '.join(comp_text))
def output_security_sub(sub: str, software: Optional[Software], client_audit: bool, padlen: int) -> None:
secdb = VersionVulnerabilityDB.CVE if sub == 'cve' else VersionVulnerabilityDB.TXT
if software is None or software.product not in secdb:
return
for line in secdb[software.product]:
vfrom = '' # type: str
vtill = '' # type: str
vfrom, vtill = line[0:2]
if not software.between_versions(vfrom, vtill):
continue
target = 0 # type: int
name = '' # type: str
target, name = line[2:4]
is_server = target & 1 == 1
is_client = target & 2 == 2
# is_local = target & 4 == 4
# If this security entry applies only to servers, but we're testing a client, then skip it. Similarly, skip entries that apply only to clients, but we're testing a server.
if (is_server and not is_client and client_audit) or (is_client and not is_server and not client_audit):
continue
p = '' if out.batch else ' ' * (padlen - len(name))
if sub == 'cve':
cvss = 0.0 # type: float
descr = '' # type: str
cvss, descr = line[4:6]
# Critical CVSS scores (>= 8.0) are printed as a fail, otherwise they are printed as a warning.
out_func = out.warn
if cvss >= 8.0:
out_func = out.fail
out_func('(cve) {}{} -- (CVSSv2: {}) {}'.format(name, p, cvss, descr))
else:
descr = line[4]
out.fail('(sec) {}{} -- {}'.format(name, p, descr))
def output_security(banner: Optional[Banner], client_audit: bool, padlen: int, is_json_output: bool) -> None:
with OutputBuffer() as obuf:
if banner is not None:
software = Software.parse(banner)
output_security_sub('cve', software, client_audit, padlen)
output_security_sub('txt', software, client_audit, padlen)
if len(obuf) > 0 and not is_json_output:
out.head('# security')
obuf.flush()
out.sep()
def output_fingerprints(algs: Algorithms, is_json_output: bool, sha256: bool = True) -> None:
with OutputBuffer() as obuf:
fps = []
if algs.ssh1kex is not None:
name = 'ssh-rsa1'
fp = Fingerprint(algs.ssh1kex.host_key_fingerprint_data)
# bits = algs.ssh1kex.host_key_bits
fps.append((name, fp))
if algs.ssh2kex is not None:
host_keys = algs.ssh2kex.host_keys()
for host_key_type in algs.ssh2kex.host_keys():
if host_keys[host_key_type] is None:
continue
fp = Fingerprint(host_keys[host_key_type])
# Workaround for Python's order-indifference in dicts. We might get a random RSA type (ssh-rsa, rsa-sha2-256, or rsa-sha2-512), so running the tool against the same server three times may give three different host key types here. So if we have any RSA type, we will simply hard-code it to 'ssh-rsa'.
if host_key_type in HostKeyTest.RSA_FAMILY:
host_key_type = 'ssh-rsa'
# Skip over certificate host types (or we would return invalid fingerprints).
if '-cert-' not in host_key_type:
fps.append((host_key_type, fp))
# Similarly, the host keys can be processed in random order due to Python's order-indifference in dicts. So we sort this list before printing; this makes automated testing possible.
fps = sorted(fps)
for fpp in fps:
name, fp = fpp
fpo = fp.sha256 if sha256 else fp.md5
# p = '' if out.batch else ' ' * (padlen - len(name))
# out.good('(fin) {0}{1} -- {2} {3}'.format(name, p, bits, fpo))
out.good('(fin) {}: {}'.format(name, fpo))
if len(obuf) > 0 and not is_json_output:
out.head('# fingerprints')
obuf.flush()
out.sep()
# Returns True if no warnings or failures encountered in configuration.
def output_recommendations(algs: Algorithms, software: Optional[Software], is_json_output: bool, padlen: int = 0) -> bool:
ret = True
# PuTTY's algorithms cannot be modified, so there's no point in issuing recommendations.
if (software is not None) and (software.product == Product.PuTTY):
max_vuln_version = 0.0
max_cvssv2_severity = 0.0
# Search the CVE database for the most recent vulnerable version and the max CVSSv2 score.
for cve_list in VersionVulnerabilityDB.CVE['PuTTY']:
vuln_version = float(cve_list[1])
cvssv2_severity = cve_list[4]
if vuln_version > max_vuln_version:
max_vuln_version = vuln_version
if cvssv2_severity > max_cvssv2_severity:
max_cvssv2_severity = cvssv2_severity
fn = out.warn
if max_cvssv2_severity > 8.0:
fn = out.fail
# Assuming that PuTTY versions will always increment by 0.01, we can calculate the first safe version by adding 0.01 to the latest vulnerable version.
current_version = float(software.version)
upgrade_to_version = max_vuln_version + 0.01
if current_version < upgrade_to_version:
out.head('# recommendations')
fn('(rec) Upgrade to PuTTY v%.2f' % upgrade_to_version)
out.sep()
ret = False
return ret
for_server = True
with OutputBuffer() as obuf:
software, alg_rec = algs.get_recommendations(software, for_server)
for sshv in range(2, 0, -1):
if sshv not in alg_rec:
continue
for alg_type in ['kex', 'key', 'enc', 'mac']:
if alg_type not in alg_rec[sshv]:
continue
for action in ['del', 'add', 'chg']:
if action not in alg_rec[sshv][alg_type]:
continue
for name in alg_rec[sshv][alg_type][action]:
p = '' if out.batch else ' ' * (padlen - len(name))
chg_additional_info = ''
if action == 'del':
an, sg, fn = 'remove', '-', out.warn
ret = False
if alg_rec[sshv][alg_type][action][name] >= 10:
fn = out.fail
elif action == 'add':
an, sg, fn = 'append', '+', out.good
elif action == 'chg':
an, sg, fn = 'change', '!', out.fail
ret = False
chg_additional_info = ' (increase modulus size to 2048 bits or larger)'
b = '(SSH{})'.format(sshv) if sshv == 1 else ''
fm = '(rec) {0}{1}{2}-- {3} algorithm to {4}{5} {6}'
fn(fm.format(sg, name, p, alg_type, an, chg_additional_info, b))
if len(obuf) > 0 and not is_json_output:
if software is not None:
title = '(for {})'.format(software.display(False))
else:
title = ''
out.head('# algorithm recommendations {}'.format(title))
obuf.flush(True) # Sort the output so that it is always stable (needed for repeatable testing).
out.sep()
return ret
# Output additional information & notes.
def output_info(software: Optional['Software'], client_audit: bool, any_problems: bool, is_json_output: bool) -> None:
with OutputBuffer() as obuf:
# Tell user that PuTTY cannot be hardened at the protocol-level.
if client_audit and (software is not None) and (software.product == Product.PuTTY):
out.warn('(nfo) PuTTY does not have the option of restricting any algorithms during the SSH handshake.')
# If any warnings or failures were given, print a link to the hardening guides.
if any_problems:
out.warn('(nfo) For hardening guides on common OSes, please see: <https://www.ssh-audit.com/hardening_guides.html>')
if len(obuf) > 0 and not is_json_output:
out.head('# additional info')
obuf.flush()
out.sep()
# Returns a exitcodes.* flag to denote if any failures or warnings were encountered.
def output(aconf: AuditConf, banner: Optional[Banner], header: List[str], client_host: Optional[str] = None, kex: Optional[SSH2_Kex] = None, pkm: Optional[SSH1_PublicKeyMessage] = None, print_target: bool = False) -> int:
program_retval = exitcodes.GOOD
client_audit = client_host is not None # If set, this is a client audit.
sshv = 1 if pkm is not None else 2
algs = Algorithms(pkm, kex)
with OutputBuffer() as obuf:
if print_target:
host = aconf.host
# Print the port if it's not the default of 22.
if aconf.port != 22:
# Check if this is an IPv6 address, as that is printed in a different format.
if Utils.is_ipv6_address(aconf.host):
host = '[%s]:%d' % (aconf.host, aconf.port)
else:
host = '%s:%d' % (aconf.host, aconf.port)
out.good('(gen) target: {}'. format(host))
if client_audit:
out.good('(gen) client IP: {}'.format(client_host))
if len(header) > 0:
out.info('(gen) header: ' + '\n'.join(header))
if banner is not None:
out.good('(gen) banner: {}'.format(banner))
if not banner.valid_ascii:
# NOTE: RFC 4253, Section 4.2
out.warn('(gen) banner contains non-printable ASCII')
if sshv == 1 or banner.protocol[0] == 1:
out.fail('(gen) protocol SSH1 enabled')
software = Software.parse(banner)
if software is not None:
out.good('(gen) software: {}'.format(software))
else:
software = None
output_compatibility(algs, client_audit)
if kex is not None:
compressions = [x for x in kex.server.compression if x != 'none']
if len(compressions) > 0:
cmptxt = 'enabled ({})'.format(', '.join(compressions))
else:
cmptxt = 'disabled'
out.good('(gen) compression: {}'.format(cmptxt))
if len(obuf) > 0 and not aconf.json: # Print output when it exists and JSON output isn't requested.
out.head('# general')
obuf.flush()
out.sep()
maxlen = algs.maxlen + 1
output_security(banner, client_audit, maxlen, aconf.json)
# Filled in by output_algorithms() with unidentified algs.
unknown_algorithms = [] # type: List[str]
if pkm is not None:
adb = SSH1_KexDB.ALGORITHMS
ciphers = pkm.supported_ciphers
auths = pkm.supported_authentications
title, atype = 'SSH1 host-key algorithms', 'key'
program_retval = output_algorithms(title, adb, atype, ['ssh-rsa1'], unknown_algorithms, aconf.json, program_retval, maxlen)
title, atype = 'SSH1 encryption algorithms (ciphers)', 'enc'
program_retval = output_algorithms(title, adb, atype, ciphers, unknown_algorithms, aconf.json, program_retval, maxlen)
title, atype = 'SSH1 authentication types', 'aut'
program_retval = output_algorithms(title, adb, atype, auths, unknown_algorithms, aconf.json, program_retval, maxlen)
if kex is not None:
adb = SSH2_KexDB.ALGORITHMS
title, atype = 'key exchange algorithms', 'kex'
program_retval = output_algorithms(title, adb, atype, kex.kex_algorithms, unknown_algorithms, aconf.json, program_retval, maxlen, kex.dh_modulus_sizes())
title, atype = 'host-key algorithms', 'key'
program_retval = output_algorithms(title, adb, atype, kex.key_algorithms, unknown_algorithms, aconf.json, program_retval, maxlen, kex.rsa_key_sizes())
title, atype = 'encryption algorithms (ciphers)', 'enc'
program_retval = output_algorithms(title, adb, atype, kex.server.encryption, unknown_algorithms, aconf.json, program_retval, maxlen)
title, atype = 'message authentication code algorithms', 'mac'
program_retval = output_algorithms(title, adb, atype, kex.server.mac, unknown_algorithms, aconf.json, program_retval, maxlen)
output_fingerprints(algs, aconf.json, True)
perfect_config = output_recommendations(algs, software, aconf.json, maxlen)
output_info(software, client_audit, not perfect_config, aconf.json)
if aconf.json:
print(json.dumps(build_struct(banner, kex=kex, client_host=client_host), sort_keys=True), end='' if len(aconf.target_list) > 0 else "\n") # Print the JSON of the audit info. Skip the newline at the end if multiple targets were given (since each audit dump will go into its own list entry).
elif len(unknown_algorithms) > 0: # If we encountered any unknown algorithms, ask the user to report them.
out.warn("\n\n!!! WARNING: unknown algorithm(s) found!: %s. Please email the full output above to the maintainer (jtesta@positronsecurity.com), or create a Github issue at <https://github.com/jtesta/ssh-audit/issues>.\n" % ','.join(unknown_algorithms))
return program_retval
def evaluate_policy(aconf: AuditConf, banner: Optional['Banner'], client_host: Optional[str], kex: Optional['SSH2_Kex'] = None) -> bool:
if aconf.policy is None:
raise RuntimeError('Internal error: cannot evaluate against null Policy!')
passed, error_struct, error_str = aconf.policy.evaluate(banner, kex)
if aconf.json:
json_struct = {'host': aconf.host, 'policy': aconf.policy.get_name_and_version(), 'passed': passed, 'errors': error_struct}
print(json.dumps(json_struct, sort_keys=True))
else:
spacing = ''
if aconf.client_audit:
print("Client IP: %s" % client_host)
spacing = " " # So the fields below line up with 'Client IP: '.
else:
host = aconf.host
if aconf.port != 22:
# Check if this is an IPv6 address, as that is printed in a different format.
if Utils.is_ipv6_address(aconf.host):
host = '[%s]:%d' % (aconf.host, aconf.port)
else:
host = '%s:%d' % (aconf.host, aconf.port)
print("Host: %s" % host)
print("Policy: %s%s" % (spacing, aconf.policy.get_name_and_version()))
print("Result: %s" % spacing, end='')
# Use these nice unicode characters in the result message, unless we're on Windows (the cmd.exe terminal doesn't display them properly).
icon_good = "✔ "
icon_fail = "❌ "
if Utils.is_windows():
icon_good = ""
icon_fail = ""
if passed:
out.good("%sPassed" % icon_good)
else:
out.fail("%sFailed!" % icon_fail)
out.warn("\nErrors:\n%s" % error_str)
return passed
def list_policies() -> None:
# Get a list of all the files in the policies sub-directory, relative to the path of this script.
installed_dir = os.path.dirname(os.path.abspath(__file__))
policies_dir = os.path.join(installed_dir, 'policies')
# If the path is not a directory, print a useful error and exit.
if not os.path.isdir(policies_dir):
print("Error: could not find policies directory. Please report this full output to <%s>:" % GITHUB_ISSUES_URL)
print("\nsys.argv[0]: %s" % sys.argv[0])
print("__file__: %s" % __file__)
print("policies_dir: %s" % policies_dir)
sys.exit(exitcodes.UNKNOWN_ERROR)
# Get a list of all the files in the policies sub-directory.
files = []
for f in os.listdir(policies_dir):
files.append(f)
files.sort() # Now the files will be in order, like 'ubuntu_client_16_04.txt', 'ubuntu_client_18_04.txt', 'ubuntu_client_20_04.txt', ...
server_policies_summary = []
client_policies_summary = []
for f in files:
# Load each policy, and generate a short summary from its name and absolute file path.
policy_file = os.path.join(policies_dir, f)
policy = Policy(policy_file=policy_file)
policy_summary = "Name: %s\nPolicy path: %s" % (policy.get_name_and_version(), policy_file)
# We will print the server policies separately from thee client policies...
if policy.is_server_policy():
server_policies_summary.append(policy_summary)
else:
client_policies_summary.append(policy_summary)
if len(server_policies_summary) > 0:
out.head('\nServer policies:\n')
print("\n\n".join(server_policies_summary))
print()
if len(client_policies_summary) > 0:
out.head('\nClient policies:\n')
print("\n\n".join(client_policies_summary))
print()
if len(server_policies_summary) == 0 and len(client_policies_summary) == 0:
print("Error: no built-in policies found in %s." % policies_dir)
else:
print("\nHint: Use -P and provide the path to a policy to run a policy scan.\n")
def make_policy(aconf: AuditConf, banner: Optional['Banner'], kex: Optional['SSH2_Kex'], client_host: Optional[str]) -> None:
# Set the source of this policy to the server host if this is a server audit, otherwise set it to the client address.
source = aconf.host # type: Optional[str]
if aconf.client_audit:
source = client_host
policy_data = Policy.create(source, banner, kex, aconf.client_audit)
if aconf.policy_file is None:
raise RuntimeError('Internal error: cannot write policy file since filename is None!')
# Open with mode 'x' (creates the file, or fails if it already exist).
succeeded = True
try:
with open(aconf.policy_file, 'x') as f:
f.write(policy_data)
except FileExistsError:
succeeded = False
if succeeded:
print("Wrote policy to %s. Customize as necessary, then run a policy scan with -P option." % aconf.policy_file)
else:
print("Error: file already exists: %s" % aconf.policy_file)
def process_commandline(args: List[str], usage_cb: Callable[..., None]) -> 'AuditConf': # pylint: disable=too-many-statements
# pylint: disable=too-many-branches
aconf = AuditConf()
try:
sopts = 'h1246M:p:P:jbcnvl:t:T:L'
lopts = ['help', 'ssh1', 'ssh2', 'ipv4', 'ipv6', 'make-policy=', 'port=', 'policy=', 'json', 'batch', 'client-audit', 'no-colors', 'verbose', 'level=', 'timeout=', 'targets=', 'list-policies', 'lookup=']
opts, args = getopt.gnu_getopt(args, sopts, lopts)
except getopt.GetoptError as err:
usage_cb(str(err))
aconf.ssh1, aconf.ssh2 = False, False
host = '' # type: str
oport = None # type: Optional[str]
port = 0 # type: int
for o, a in opts:
if o in ('-h', '--help'):
usage_cb()
elif o in ('-1', '--ssh1'):
aconf.ssh1 = True
elif o in ('-2', '--ssh2'):
aconf.ssh2 = True
elif o in ('-4', '--ipv4'):
aconf.ipv4 = True
elif o in ('-6', '--ipv6'):
aconf.ipv6 = True
elif o in ('-p', '--port'):
oport = a
elif o in ('-b', '--batch'):
aconf.batch = True
aconf.verbose = True
elif o in ('-c', '--client-audit'):
aconf.client_audit = True
elif o in ('-n', '--no-colors'):
aconf.colors = False
elif o in ('-j', '--json'):
aconf.json = True
elif o in ('-v', '--verbose'):
aconf.verbose = True
elif o in ('-l', '--level'):
if a not in ('info', 'warn', 'fail'):
usage_cb('level {} is not valid'.format(a))
aconf.level = a
elif o in ('-t', '--timeout'):
aconf.timeout = float(a)
aconf.timeout_set = True
elif o in ('-M', '--make-policy'):
aconf.make_policy = True
aconf.policy_file = a
elif o in ('-P', '--policy'):
aconf.policy_file = a
elif o in ('-T', '--targets'):
aconf.target_file = a
elif o in ('-L', '--list-policies'):
aconf.list_policies = True
elif o == '--lookup':
aconf.lookup = a
if len(args) == 0 and aconf.client_audit is False and aconf.target_file is None and aconf.list_policies is False and aconf.lookup == '':
usage_cb()
if aconf.lookup != '':
return aconf
if aconf.list_policies:
list_policies()
sys.exit(exitcodes.GOOD)
if aconf.client_audit is False and aconf.target_file is None:
if oport is not None:
host = args[0]
else:
host, port = Utils.parse_host_and_port(args[0])
if not host and aconf.target_file is None:
usage_cb('host is empty')
if port == 0 and oport is None:
if aconf.client_audit: # The default port to listen on during a client audit is 2222.
port = 2222
else:
port = 22
if oport is not None:
port = Utils.parse_int(oport)
if port <= 0 or port > 65535:
usage_cb('port {} is not valid'.format(oport))
aconf.host = host
aconf.port = port
if not (aconf.ssh1 or aconf.ssh2):
aconf.ssh1, aconf.ssh2 = True, True
# If a file containing a list of targets was given, read it.
if aconf.target_file is not None:
with open(aconf.target_file, 'r') as f:
aconf.target_list = f.readlines()
# Strip out whitespace from each line in target file, and skip empty lines.
aconf.target_list = [target.strip() for target in aconf.target_list if target not in ("", "\n")]
# If a policy file was provided, validate it.
if (aconf.policy_file is not None) and (aconf.make_policy is False):
try:
aconf.policy = Policy(policy_file=aconf.policy_file)
except Exception as e:
print("Error while loading policy file: %s: %s" % (str(e), traceback.format_exc()))
sys.exit(exitcodes.UNKNOWN_ERROR)
# If the user wants to do a client audit, but provided a server policy, terminate.
if aconf.client_audit and aconf.policy.is_server_policy():
print("Error: client audit selected, but server policy provided.")
sys.exit(exitcodes.UNKNOWN_ERROR)
# If the user wants to do a server audit, but provided a client policy, terminate.
if aconf.client_audit is False and aconf.policy.is_server_policy() is False:
print("Error: server audit selected, but client policy provided.")
sys.exit(exitcodes.UNKNOWN_ERROR)
return aconf
def build_struct(banner: Optional['Banner'], kex: Optional['SSH2_Kex'] = None, pkm: Optional['SSH1_PublicKeyMessage'] = None, client_host: Optional[str] = None) -> Any:
banner_str = ''
banner_protocol = None
banner_software = None
banner_comments = None
if banner is not None:
banner_str = str(banner)
banner_protocol = banner.protocol
banner_software = banner.software
banner_comments = banner.comments
res = {
"banner": {
"raw": banner_str,
"protocol": banner_protocol,
"software": banner_software,
"comments": banner_comments,
},
} # type: Any
if client_host is not None:
res['client_ip'] = client_host
if kex is not None:
res['compression'] = kex.server.compression
res['kex'] = []
alg_sizes = kex.dh_modulus_sizes()
for algorithm in kex.kex_algorithms:
entry = {
'algorithm': algorithm,
} # type: Any
if algorithm in alg_sizes:
hostkey_size, ca_size = alg_sizes[algorithm]
entry['keysize'] = hostkey_size
if ca_size > 0:
entry['casize'] = ca_size
res['kex'].append(entry)
res['key'] = []
alg_sizes = kex.rsa_key_sizes()
for algorithm in kex.key_algorithms:
entry = {
'algorithm': algorithm,
}
if algorithm in alg_sizes:
hostkey_size, ca_size = alg_sizes[algorithm]
entry['keysize'] = hostkey_size
if ca_size > 0:
entry['casize'] = ca_size
res['key'].append(entry)
res['enc'] = kex.server.encryption
res['mac'] = kex.server.mac
res['fingerprints'] = []
host_keys = kex.host_keys()
# Normalize all RSA key types to 'ssh-rsa'. Otherwise, due to Python's order-indifference dictionary types, we would iterate key types in unpredictable orders, which interferes with the docker testing framework (i.e.: tests would fail because elements are reported out of order, even though the output is semantically the same).
for host_key_type in list(host_keys.keys())[:]:
if host_key_type in HostKeyTest.RSA_FAMILY:
val = host_keys[host_key_type]
del host_keys[host_key_type]
host_keys['ssh-rsa'] = val
for host_key_type in sorted(host_keys):
if host_keys[host_key_type] is None:
continue
fp = Fingerprint(host_keys[host_key_type])
# Skip over certificate host types (or we would return invalid fingerprints).
if '-cert-' in host_key_type:
continue
entry = {
'type': host_key_type,
'fp': fp.sha256,
}
res['fingerprints'].append(entry)
else:
pkm_supported_ciphers = None
pkm_supported_authentications = None
pkm_fp = None
if pkm is not None:
pkm_supported_ciphers = pkm.supported_ciphers
pkm_supported_authentications = pkm.supported_authentications
pkm_fp = Fingerprint(pkm.host_key_fingerprint_data).sha256
res['key'] = ['ssh-rsa1']
res['enc'] = pkm_supported_ciphers
res['aut'] = pkm_supported_authentications
res['fingerprints'] = [{
'type': 'ssh-rsa1',
'fp': pkm_fp,
}]
return res
# Returns one of the exitcodes.* flags.
def audit(aconf: AuditConf, sshv: Optional[int] = None, print_target: bool = False) -> int:
program_retval = exitcodes.GOOD
out.batch = aconf.batch
out.verbose = aconf.verbose
out.level = aconf.level
out.use_colors = aconf.colors
s = SSH_Socket(aconf.host, aconf.port, aconf.ipvo, aconf.timeout, aconf.timeout_set)
if aconf.client_audit:
s.listen_and_accept()
else:
err = s.connect()
if err is not None:
out.fail(err)
sys.exit(exitcodes.CONNECTION_ERROR)
if sshv is None:
sshv = 2 if aconf.ssh2 else 1
err = None
banner, header, err = s.get_banner(sshv)
if banner is None:
if err is None:
err = '[exception] did not receive banner.'
else:
err = '[exception] did not receive banner: {}'.format(err)
if err is None:
s.send_algorithms() # Send the algorithms we support (except we don't since this isn't a real SSH connection).
packet_type, payload = s.read_packet(sshv)
if packet_type < 0:
try:
if len(payload) > 0:
payload_txt = payload.decode('utf-8')
else:
payload_txt = u'empty'
except UnicodeDecodeError:
payload_txt = u'"{}"'.format(repr(payload).lstrip('b')[1:-1])
if payload_txt == u'Protocol major versions differ.':
if sshv == 2 and aconf.ssh1:
return audit(aconf, 1)
err = '[exception] error reading packet ({})'.format(payload_txt)
else:
err_pair = None
if sshv == 1 and packet_type != Protocol.SMSG_PUBLIC_KEY:
err_pair = ('SMSG_PUBLIC_KEY', Protocol.SMSG_PUBLIC_KEY)
elif sshv == 2 and packet_type != Protocol.MSG_KEXINIT:
err_pair = ('MSG_KEXINIT', Protocol.MSG_KEXINIT)
if err_pair is not None:
fmt = '[exception] did not receive {0} ({1}), ' + \
'instead received unknown message ({2})'
err = fmt.format(err_pair[0], err_pair[1], packet_type)
if err is not None:
output(aconf, banner, header)
out.fail(err)
return exitcodes.CONNECTION_ERROR
if sshv == 1:
program_retval = output(aconf, banner, header, pkm=SSH1_PublicKeyMessage.parse(payload))
elif sshv == 2:
kex = SSH2_Kex.parse(payload)
if aconf.client_audit is False:
HostKeyTest.run(s, kex)
GEXTest.run(s, kex)
# This is a standard audit scan.
if (aconf.policy is None) and (aconf.make_policy is False):
program_retval = output(aconf, banner, header, client_host=s.client_host, kex=kex, print_target=print_target)
# This is a policy test.
elif (aconf.policy is not None) and (aconf.make_policy is False):
program_retval = exitcodes.GOOD if evaluate_policy(aconf, banner, s.client_host, kex=kex) else exitcodes.FAILURE
# A new policy should be made from this scan.
elif (aconf.policy is None) and (aconf.make_policy is True):
make_policy(aconf, banner, kex, s.client_host)
else:
raise RuntimeError('Internal error while handling output: %r %r' % (aconf.policy is None, aconf.make_policy))
return program_retval
def algorithm_lookup(alg_names: str) -> int:
'''Looks up a comma-separated list of algorithms and outputs their security properties. Returns an exitcodes.* flag.'''
retval = exitcodes.GOOD
alg_types = {
'kex': 'key exchange algorithms',
'key': 'host-key algorithms',
'mac': 'message authentication code algorithms',
'enc': 'encryption algorithms (ciphers)'
}
algorithm_names = alg_names.split(",")
adb = SSH2_KexDB.ALGORITHMS
# Use nested dictionary comprehension to iterate an outer dictionary where
# each key is an alg type that consists of a value (which is itself a
# dictionary) of alg names. Filter the alg names against the user supplied
# list of names.
algorithms_dict = {
outer_k: {
inner_k
for (inner_k, inner_v) in outer_v.items()
if inner_k in algorithm_names
}
for (outer_k, outer_v) in adb.items()
}
unknown_algorithms = [] # type: List[str]
padding = len(max(algorithm_names, key=len))
for alg_type in alg_types:
if len(algorithms_dict[alg_type]) > 0:
title = str(alg_types.get(alg_type))
retval = output_algorithms(title, adb, alg_type, list(algorithms_dict[alg_type]), unknown_algorithms, False, retval, padding)
algorithms_dict_flattened = [
alg_name
for val in algorithms_dict.values()
for alg_name in val
]
algorithms_not_found = [
alg_name
for alg_name in algorithm_names
if alg_name not in algorithms_dict_flattened
]
if len(algorithms_not_found) > 0:
retval = exitcodes.FAILURE
out.head('# unknown algorithms')
for algorithm_not_found in algorithms_not_found:
out.fail(algorithm_not_found)
return retval
out = Output()
def main() -> int:
aconf = process_commandline(sys.argv[1:], usage)
if aconf.lookup != '':
retval = algorithm_lookup(aconf.lookup)
sys.exit(retval)
# If multiple targets were specified...
if len(aconf.target_list) > 0:
ret = exitcodes.GOOD
# If JSON output is desired, each target's results will be reported in its own list entry.
if aconf.json:
print('[', end='')
# Loop through each target in the list.
for i, target in enumerate(aconf.target_list):
aconf.host, port = Utils.parse_host_and_port(target)
if port == 0:
port = 22
aconf.port = port
new_ret = audit(aconf, print_target=True)
# Set the return value only if an unknown error occurred, a failure occurred, or if a warning occurred and the previous value was good.
if (new_ret == exitcodes.UNKNOWN_ERROR) or (new_ret == exitcodes.FAILURE) or ((new_ret == exitcodes.WARNING) and (ret == exitcodes.GOOD)):
ret = new_ret
# Don't print a delimiter after the last target was handled.
if i + 1 != len(aconf.target_list):
if aconf.json:
print(", ", end='')
else:
print(("-" * 80) + "\n")
if aconf.json:
print(']')
return ret
else:
return audit(aconf)
if __name__ == '__main__': # pragma: nocover
exit_code = exitcodes.GOOD
try:
exit_code = main()
except Exception:
exit_code = exitcodes.UNKNOWN_ERROR
print(traceback.format_exc())
sys.exit(exit_code)
Reference in New Issue View Git Blame Copy Permalink