Removed SSHv1 support (#298).

README.md

@@ -26,8 +26,7 @@
 - [ChangeLog](#changelog)
 
 ## Features
-- SSH1 and SSH2 protocol server support;
+- analyze SSH both server and client configuration;
-- analyze SSH client configuration;
 - grab banner, recognize device or software and operating system, detect compression;
 - gather key-exchange, host-key, encryption and message authentication code algorithms;
 - output algorithm security information (available since, removed/disabled, unsafe/weak/legacy, etc);
@@ -41,7 +40,7 @@
 
 ## Usage
 ```
-usage: ssh-audit.py [-h] [-1] [-2] [-4] [-6] [-b] [-c] [-d]
+usage: ssh-audit.py [-h] [-4] [-6] [-b] [-c] [-d]
                     [-g <min1:pref1:max1[,min2:pref2:max2,...]> / <x-y[:step]>] [-j] [-l {info,warn,fail}] [-L]
                     [-M custom_policy.txt] [-m] [-n] [-P "Built-In Policy Name" / custom_policy.txt] [-p N]
                     [-T targets.txt] [-t N] [-v] [--conn-rate-test N[:max_rate]] [--dheat N[:kex[:e_len]]]
@@ -53,8 +52,6 @@ positional arguments:
 
 optional arguments:
   -h, --help            show this help message and exit
-  -1, --ssh1            force ssh version 1 only
-  -2, --ssh2            force ssh version 2 only
   -4, --ipv4            enable IPv4 (order of precedence)
   -6, --ipv6            enable IPv6 (order of precedence)
   -b, --batch           batch output
@@ -218,6 +215,7 @@ For convenience, a web front-end on top of the command-line tool is available at
 
 ### v3.4.0-dev
  - Added warning to all key exchanges that do not include protections against quantum attacks due to the Harvest Now, Decrypt Later strategy (see https://en.wikipedia.org/wiki/Harvest_now,_decrypt_later).
+ - Removed SSHv1 support (rationale is documented in: https://github.com/jtesta/ssh-audit/issues/298).
  - Migrated from deprecated `getopt` module to `argparse`; partial credit [oam7575](https://github.com/oam7575).
  - When running against multiple hosts, now prints each target host regardless of output level.
  - Batch mode (`-b`) no longer automatically enables verbose mode, due to sometimes confusing results; users can still explicitly enable verbose mode using the `-v` flag.

src/ssh_audit/algorithms.py

@@ -1,7 +1,7 @@
 """
    The MIT License (MIT)
 
-   Copyright (C) 2017-2021 Joe Testa (jtesta@positronsecurity.com)
+   Copyright (C) 2017-2025 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
@@ -29,8 +29,6 @@ from typing import Callable, Optional, Union, Any  # noqa: F401
 from ssh_audit.algorithm import Algorithm
 from ssh_audit.product import Product
 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.timeframe import Timeframe
@@ -38,28 +36,13 @@ from ssh_audit.utils import Utils
 
 
 class Algorithms:
-    def __init__(self, pkm: Optional[SSH1_PublicKeyMessage], kex: Optional[SSH2_Kex]) -> None:
+    def __init__(self, kex: Optional[SSH2_Kex]) -> None:
-        self.__ssh1kex = pkm
         self.__ssh2kex = kex
 
-    @property
-    def ssh1kex(self) -> Optional[SSH1_PublicKeyMessage]:
-        return self.__ssh1kex
-
     @property
     def ssh2kex(self) -> Optional[SSH2_Kex]:
         return self.__ssh2kex
 
-    @property
-    def ssh1(self) -> Optional['Algorithms.Item']:
-        if self.ssh1kex is None:
-            return None
-        item = Algorithms.Item(1, SSH1_KexDB.get_db())
-        item.add('key', ['ssh-rsa1'])
-        item.add('enc', self.ssh1kex.supported_ciphers)
-        item.add('aut', self.ssh1kex.supported_authentications)
-        return item
-
     @property
     def ssh2(self) -> Optional['Algorithms.Item']:
         if self.ssh2kex is None:
@@ -73,7 +56,7 @@ class Algorithms:
 
     @property
     def values(self) -> Iterable['Algorithms.Item']:
-        for item in [self.ssh1, self.ssh2]:
+        for item in [self.ssh2]:
             if item is not None:
                 yield item
 
@@ -82,10 +65,6 @@ class Algorithms:
         def _ml(items: Sequence[str]) -> int:
             return max(len(i) for i in items)
         maxlen = 0
-        if self.ssh1kex is not None:
-            maxlen = max(_ml(self.ssh1kex.supported_ciphers),
-                         _ml(self.ssh1kex.supported_authentications),
-                         maxlen)
         if self.ssh2kex is not None:
             maxlen = max(_ml(self.ssh2kex.kex_algorithms),
                          _ml(self.ssh2kex.key_algorithms),

src/ssh_audit/auditconf.py

@@ -1,7 +1,7 @@
 """
    The MIT License (MIT)
 
-   Copyright (C) 2017-2024 Joe Testa (jtesta@positronsecurity.com)
+   Copyright (C) 2017-2025 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
@@ -35,8 +35,6 @@ class AuditConf:
     def __init__(self, host: str = '', port: int = 22) -> None:
         self.host = host
         self.port = port
-        self.ssh1 = True
-        self.ssh2 = True
         self.batch = False
         self.client_audit = False
         self.colors = True
@@ -73,7 +71,7 @@ class AuditConf:
 
     def __setattr__(self, name: str, value: Union[str, int, float, bool, Sequence[int]]) -> None:
         valid = False
-        if name in ['batch', 'client_audit', 'colors', 'json', 'json_print_indent', 'list_policies', 'manual', 'make_policy', 'ssh1', 'ssh2', 'timeout_set', 'verbose', 'debug', 'skip_rate_test']:
+        if name in ['batch', 'client_audit', 'colors', 'json', 'json_print_indent', 'list_policies', 'manual', 'make_policy', 'timeout_set', 'verbose', 'debug', 'skip_rate_test']:
             valid, value = True, bool(value)
         elif name in ['ipv4', 'ipv6']:
             valid, value = True, bool(value)

src/ssh_audit/gextest.py

@@ -1,7 +1,7 @@
 """
    The MIT License (MIT)
 
-   Copyright (C) 2017-2023 Joe Testa (jtesta@positronsecurity.com)
+   Copyright (C) 2017-2025 Joe Testa (jtesta@positronsecurity.com)
 
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
@@ -64,7 +64,7 @@ class GEXTest:
 
         try:
             # Parse the server's KEX.
-            _, payload = s.read_packet(2)
+            _, payload = s.read_packet()
             SSH2_Kex.parse(out, payload)
         except (KexDHException, struct.error):
             out.v("Failed to parse server's kex.  Stack trace:\n%s" % str(traceback.format_exc()), write_now=True)

src/ssh_audit/kexdh.py

@@ -1,7 +1,7 @@
 """
    The MIT License (MIT)
 
-   Copyright (C) 2017-2023 Joe Testa (jtesta@positronsecurity.com)
+   Copyright (C) 2017-2025 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
@@ -88,11 +88,11 @@ class KexDH:  # pragma: nocover
         self.__ca_key_type = ''
         self.__ca_n_len = 0
 
-        packet_type, payload = s.read_packet(2)
+        packet_type, payload = s.read_packet()
 
         # Skip any & all MSG_DEBUG messages.
         while packet_type == Protocol.MSG_DEBUG:
-            packet_type, payload = s.read_packet(2)
+            packet_type, payload = s.read_packet()
 
         if packet_type != -1 and packet_type not in [Protocol.MSG_KEXDH_REPLY, Protocol.MSG_KEXDH_GEX_REPLY]:  # pylint: disable=no-else-raise
             raise KexDHException('Expected MSG_KEXDH_REPLY (%d) or MSG_KEXDH_GEX_REPLY (%d), but got %d instead.' % (Protocol.MSG_KEXDH_REPLY, Protocol.MSG_KEXDH_GEX_REPLY, packet_type))
@@ -380,13 +380,13 @@ class KexGroupExchange(KexDH):
         s.write_int(maxbits)
         s.send_packet()
 
-        packet_type, payload = s.read_packet(2)
+        packet_type, payload = s.read_packet()
         if packet_type not in [Protocol.MSG_KEXDH_GEX_GROUP, Protocol.MSG_DEBUG]:
             raise KexDHException('Expected MSG_KEXDH_GEX_REPLY (%d), but got %d instead.' % (Protocol.MSG_KEXDH_GEX_REPLY, packet_type))
 
         # Skip any & all MSG_DEBUG messages.
         while packet_type == Protocol.MSG_DEBUG:
-            packet_type, payload = s.read_packet(2)
+            packet_type, payload = s.read_packet()
 
         try:
             # Parse the modulus (p) and generator (g) values from the server.

src/ssh_audit/ssh1.py

@@ -1,40 +0,0 @@
-"""
-   The MIT License (MIT)
-
-   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.
-"""
-# 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.ssh1_crc32 import SSH1_CRC32
-
-
-class SSH1:
-    _crc32: Optional[SSH1_CRC32] = None
-    CIPHERS = ['none', 'idea', 'des', '3des', 'tss', 'rc4', 'blowfish']
-    AUTHS = ['none', 'rhosts', 'rsa', 'password', 'rhosts_rsa', 'tis', 'kerberos']
-
-    @classmethod
-    def crc32(cls, v: bytes) -> int:
-        if cls._crc32 is None:
-            cls._crc32 = SSH1_CRC32()
-        return cls._crc32.calc(v)

src/ssh_audit/ssh1_crc32.py

@@ -1,47 +0,0 @@
-"""
-   The MIT License (MIT)
-
-   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.
-"""
-# pylint: disable=unused-import
-from typing import Dict, List, Set, Sequence, Tuple, Iterable  # noqa: F401
-from typing import Callable, Optional, Union, Any  # noqa: F401
-
-
-class SSH1_CRC32:
-    def __init__(self) -> None:
-        self._table = [0] * 256
-        for i in range(256):
-            crc = 0
-            n = i
-            for _ in range(8):
-                x = (crc ^ n) & 1
-                crc = (crc >> 1) ^ (x * 0xedb88320)
-                n = n >> 1
-                self._table[i] = crc
-
-    def calc(self, v: bytes) -> int:
-        crc, length = 0, len(v)
-        for i in range(length):
-            n = ord(v[i:i + 1])
-            n = n ^ (crc & 0xff)
-            crc = (crc >> 8) ^ self._table[n]
-        return crc

src/ssh_audit/ssh1_kexdb.py

@@ -1,84 +0,0 @@
-"""
-   The MIT License (MIT)
-
-   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.
-"""
-# pylint: disable=unused-import
-import copy
-import threading
-
-from typing import Dict, List, Set, Sequence, Tuple, Iterable  # noqa: F401
-from typing import Callable, Optional, Union, Any  # noqa: F401
-
-
-class SSH1_KexDB:  # pylint: disable=too-few-public-methods
-
-    FAIL_PLAINTEXT = 'no encryption/integrity'
-    FAIL_OPENSSH37_REMOVE = 'removed since OpenSSH 3.7'
-    FAIL_NA_BROKEN = 'not implemented in OpenSSH, broken algorithm'
-    FAIL_NA_UNSAFE = 'not implemented in OpenSSH (server), unsafe algorithm'
-    TEXT_CIPHER_IDEA = 'cipher used by commercial SSH'
-
-    DB_PER_THREAD: Dict[int, Dict[str, Dict[str, List[List[Optional[str]]]]]] = {}
-
-    MASTER_DB: Dict[str, Dict[str, List[List[Optional[str]]]]] = {
-        'key': {
-            'ssh-rsa1': [['1.2.2']],
-        },
-        'enc': {
-            'none': [['1.2.2'], [FAIL_PLAINTEXT]],
-            'idea': [[None], [], [], [TEXT_CIPHER_IDEA]],
-            'des': [['2.3.0C'], [FAIL_NA_UNSAFE]],
-            '3des': [['1.2.2']],
-            'tss': [[''], [FAIL_NA_BROKEN]],
-            'rc4': [[], [FAIL_NA_BROKEN]],
-            'blowfish': [['1.2.2']],
-        },
-        'aut': {
-            'rhosts': [['1.2.2', '3.6'], [FAIL_OPENSSH37_REMOVE]],
-            'rsa': [['1.2.2']],
-            'password': [['1.2.2']],
-            'rhosts_rsa': [['1.2.2']],
-            'tis': [['1.2.2']],
-            'kerberos': [['1.2.2', '3.6'], [FAIL_OPENSSH37_REMOVE]],
-        }
-    }
-
-
-    @staticmethod
-    def get_db() -> Dict[str, Dict[str, List[List[Optional[str]]]]]:
-        '''Returns a copy of the MASTER_DB that is private to the calling thread.  This prevents multiple threads from polluting the results of other threads.'''
-        calling_thread_id = threading.get_ident()
-
-        if calling_thread_id not in SSH1_KexDB.DB_PER_THREAD:
-            SSH1_KexDB.DB_PER_THREAD[calling_thread_id] = copy.deepcopy(SSH1_KexDB.MASTER_DB)
-
-        return SSH1_KexDB.DB_PER_THREAD[calling_thread_id]
-
-
-    @staticmethod
-    def thread_exit() -> None:
-        '''Deletes the calling thread's copy of the MASTER_DB.  This is needed because, in rare circumstances, a terminated thread's ID can be re-used by new threads.'''
-
-        calling_thread_id = threading.get_ident()
-
-        if calling_thread_id in SSH1_KexDB.DB_PER_THREAD:
-            del SSH1_KexDB.DB_PER_THREAD[calling_thread_id]

src/ssh_audit/ssh1_publickeymessage.py

@@ -1,144 +0,0 @@
-"""
-   The MIT License (MIT)
-
-   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.
-"""
-# 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.ssh1 import SSH1
-from ssh_audit.readbuf import ReadBuf
-from ssh_audit.utils import Utils
-from ssh_audit.writebuf import WriteBuf
-
-
-class SSH1_PublicKeyMessage:
-    def __init__(self, cookie: bytes, skey: Tuple[int, int, int], hkey: Tuple[int, int, int], pflags: int, cmask: int, amask: int) -> None:
-        if len(skey) != 3:
-            raise ValueError('invalid server key pair: {}'.format(skey))
-        if len(hkey) != 3:
-            raise ValueError('invalid host key pair: {}'.format(hkey))
-        self.__cookie = cookie
-        self.__server_key = skey
-        self.__host_key = hkey
-        self.__protocol_flags = pflags
-        self.__supported_ciphers_mask = cmask
-        self.__supported_authentications_mask = amask
-
-    @property
-    def cookie(self) -> bytes:
-        return self.__cookie
-
-    @property
-    def server_key_bits(self) -> int:
-        return self.__server_key[0]
-
-    @property
-    def server_key_public_exponent(self) -> int:
-        return self.__server_key[1]
-
-    @property
-    def server_key_public_modulus(self) -> int:
-        return self.__server_key[2]
-
-    @property
-    def host_key_bits(self) -> int:
-        return self.__host_key[0]
-
-    @property
-    def host_key_public_exponent(self) -> int:
-        return self.__host_key[1]
-
-    @property
-    def host_key_public_modulus(self) -> int:
-        return self.__host_key[2]
-
-    @property
-    def host_key_fingerprint_data(self) -> bytes:
-        # pylint: disable=protected-access
-        mod = WriteBuf._create_mpint(self.host_key_public_modulus, False)
-        e = WriteBuf._create_mpint(self.host_key_public_exponent, False)
-        return mod + e
-
-    @property
-    def protocol_flags(self) -> int:
-        return self.__protocol_flags
-
-    @property
-    def supported_ciphers_mask(self) -> int:
-        return self.__supported_ciphers_mask
-
-    @property
-    def supported_ciphers(self) -> List[str]:
-        ciphers = []
-        for i in range(len(SSH1.CIPHERS)):  # pylint: disable=consider-using-enumerate
-            if self.__supported_ciphers_mask & (1 << i) != 0:
-                ciphers.append(Utils.to_text(SSH1.CIPHERS[i]))
-        return ciphers
-
-    @property
-    def supported_authentications_mask(self) -> int:
-        return self.__supported_authentications_mask
-
-    @property
-    def supported_authentications(self) -> List[str]:
-        auths = []
-        for i in range(1, len(SSH1.AUTHS)):
-            if self.__supported_authentications_mask & (1 << i) != 0:
-                auths.append(Utils.to_text(SSH1.AUTHS[i]))
-        return auths
-
-    def write(self, wbuf: 'WriteBuf') -> None:
-        wbuf.write(self.cookie)
-        wbuf.write_int(self.server_key_bits)
-        wbuf.write_mpint1(self.server_key_public_exponent)
-        wbuf.write_mpint1(self.server_key_public_modulus)
-        wbuf.write_int(self.host_key_bits)
-        wbuf.write_mpint1(self.host_key_public_exponent)
-        wbuf.write_mpint1(self.host_key_public_modulus)
-        wbuf.write_int(self.protocol_flags)
-        wbuf.write_int(self.supported_ciphers_mask)
-        wbuf.write_int(self.supported_authentications_mask)
-
-    @property
-    def payload(self) -> bytes:
-        wbuf = WriteBuf()
-        self.write(wbuf)
-        return wbuf.write_flush()
-
-    @classmethod
-    def parse(cls, payload: bytes) -> 'SSH1_PublicKeyMessage':
-        buf = ReadBuf(payload)
-        cookie = buf.read(8)
-        server_key_bits = buf.read_int()
-        server_key_exponent = buf.read_mpint1()
-        server_key_modulus = buf.read_mpint1()
-        skey = (server_key_bits, server_key_exponent, server_key_modulus)
-        host_key_bits = buf.read_int()
-        host_key_exponent = buf.read_mpint1()
-        host_key_modulus = buf.read_mpint1()
-        hkey = (host_key_bits, host_key_exponent, host_key_modulus)
-        pflags = buf.read_int()
-        cmask = buf.read_int()
-        amask = buf.read_int()
-        pkm = cls(cookie, skey, hkey, pflags, cmask, amask)
-        return pkm

src/ssh_audit/ssh_audit.py

@@ -2,7 +2,7 @@
 """
    The MIT License (MIT)
 
-   Copyright (C) 2017-2024 Joe Testa (jtesta@positronsecurity.com)
+   Copyright (C) 2017-2025 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
@@ -56,8 +56,6 @@ 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
@@ -234,11 +232,6 @@ def output_security(out: OutputBuffer, banner: Optional[Banner], padlen: int, is
 def output_fingerprints(out: OutputBuffer, algs: Algorithms, is_json_output: bool) -> None:
     with out:
         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[name] = fp
         if algs.ssh2kex is not None:
             host_keys = algs.ssh2kex.host_keys()
             for host_key_type in algs.ssh2kex.host_keys():
@@ -509,12 +502,11 @@ def post_process_findings(banner: Optional[Banner], algs: Algorithms, client_aud
 
 
 # Returns a exitcodes.* flag to denote if any failures or warnings were encountered.
-def output(out: OutputBuffer, 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, dh_rate_test_notes: str = "") -> int:
+def output(out: OutputBuffer, aconf: AuditConf, banner: Optional[Banner], header: List[str], client_host: Optional[str] = None, kex: Optional[SSH2_Kex] = None, print_target: bool = False, dh_rate_test_notes: str = "") -> 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(kex)
-    algs = Algorithms(pkm, kex)
 
     # Perform post-processing on the findings to make final adjustments before outputting the results.
     algorithm_recommendation_suppress_list, additional_notes = post_process_findings(banner, algs, client_audit, dh_rate_test_notes)
@@ -539,7 +531,7 @@ def output(out: OutputBuffer, aconf: AuditConf, banner: Optional[Banner], header
             out.info('(gen) header: ' + '\n'.join(header))
         if banner is not None:
             banner_line = '(gen) banner: {}'.format(banner)
-            if sshv == 1 or banner.protocol[0] == 1:
+            if banner.protocol[0] == 1:
                 out.fail(banner_line)
                 out.fail('(gen) protocol SSH1 enabled')
             else:
@@ -571,18 +563,6 @@ def output(out: OutputBuffer, aconf: AuditConf, banner: Optional[Banner], header
     # Filled in by output_algorithms() with unidentified algs.
     unknown_algorithms: List[str] = []
 
-    # SSHv1
-    if pkm is not None:
-        adb = SSH1_KexDB.get_db()
-        ciphers = pkm.supported_ciphers
-        auths = pkm.supported_authentications
-        title, atype = 'SSH1 host-key algorithms', 'key'
-        program_retval = output_algorithms(out, title, adb, atype, ['ssh-rsa1'], unknown_algorithms, aconf.json, program_retval, maxlen)
-        title, atype = 'SSH1 encryption algorithms (ciphers)', 'enc'
-        program_retval = output_algorithms(out, title, adb, atype, ciphers, unknown_algorithms, aconf.json, program_retval, maxlen)
-        title, atype = 'SSH1 authentication types', 'aut'
-        program_retval = output_algorithms(out, title, adb, atype, auths, unknown_algorithms, aconf.json, program_retval, maxlen)
-
     # SSHv2
     if kex is not None:
         adb = SSH2_KexDB.get_db()
@@ -782,15 +762,12 @@ def process_commandline(out: OutputBuffer, args: List[str]) -> 'AuditConf':  # p
     aconf.colors = enable_colors
     out.use_colors = enable_colors
 
-    aconf.ssh1, aconf.ssh2 = False, False
     host: str = ''
     port: int = 22
 
     parser = argparse.ArgumentParser(description="# {} {}, https://github.com/jtesta/ssh-audit".format(os.path.basename(sys.argv[0]), VERSION), allow_abbrev=False)
 
     # Add short options to the parser
-    parser.add_argument("-1", "--ssh1", action="store_true", dest="ssh1", default=False, help="force ssh version 1 only")
-    parser.add_argument("-2", "--ssh2", action="store_true", dest="ssh2", default=False, help="force ssh version 2 only")
     parser.add_argument("-4", "--ipv4", action="store_true", dest="ipv4", default=False, help="enable IPv4 (order of precedence)")
     parser.add_argument("-6", "--ipv6", action="store_true", dest="ipv6", default=False, help="enable IPv6 (order of precedence)")
     parser.add_argument("-b", "--batch", action="store_true", dest="batch", default=False, help="batch output")
@@ -836,8 +813,6 @@ def process_commandline(out: OutputBuffer, args: List[str]) -> 'AuditConf':  # p
         aconf.list_policies = argument.list_policies
         aconf.manual = argument.manual
         aconf.skip_rate_test = argument.skip_rate_test
-        aconf.ssh1 = argument.ssh1
-        aconf.ssh2 = argument.ssh2
         oport = argument.oport
 
         if argument.batch is True:
@@ -950,9 +925,6 @@ def process_commandline(out: OutputBuffer, args: List[str]) -> 'AuditConf':  # p
     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:
         try:
@@ -994,7 +966,7 @@ def process_commandline(out: OutputBuffer, args: List[str]) -> 'AuditConf':  # p
     return aconf
 
 
-def build_struct(target_host: str, banner: Optional['Banner'], kex: Optional['SSH2_Kex'] = None, pkm: Optional['SSH1_PublicKeyMessage'] = None, client_host: Optional[str] = None, software: Optional[Software] = None, algorithms: Optional[Algorithms] = None, algorithm_recommendation_suppress_list: Optional[List[str]] = None, additional_notes: List[str] = []) -> Any:  # pylint: disable=dangerous-default-value
+def build_struct(target_host: str, banner: Optional['Banner'], kex: Optional['SSH2_Kex'] = None, client_host: Optional[str] = None, software: Optional[Software] = None, algorithms: Optional[Algorithms] = None, algorithm_recommendation_suppress_list: Optional[List[str]] = None, additional_notes: List[str] = []) -> Any:  # pylint: disable=dangerous-default-value
 
     def fetch_notes(algorithm: str, alg_type: str) -> Dict[str, List[Optional[str]]]:
         '''Returns a dictionary containing the messages in the "fail", "warn", and "info" levels for this algorithm.'''
@@ -1139,22 +1111,6 @@ def build_struct(target_host: str, banner: Optional['Banner'], kex: Optional['SS
                 'hash_alg': 'MD5',
                 'hash': fp.md5[4:]
             })
-    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,
-        }]
 
     # Historically, CVE information was returned.  Now we'll just return an empty dictionary so as to not break any legacy clients.
     res['cves'] = []
@@ -1169,7 +1125,7 @@ def build_struct(target_host: str, banner: Optional['Banner'], kex: Optional['SS
 
 
 # Returns one of the exitcodes.* flags.
-def audit(out: OutputBuffer, aconf: AuditConf, sshv: Optional[int] = None, print_target: bool = False) -> int:
+def audit(out: OutputBuffer, aconf: AuditConf, print_target: bool = False) -> int:
     program_retval = exitcodes.GOOD
     out.batch = aconf.batch
     out.verbose = aconf.verbose
@@ -1195,10 +1151,8 @@ def audit(out: OutputBuffer, aconf: AuditConf, sshv: Optional[int] = None, print
                 out.write()
                 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)
+    banner, header, err = s.get_banner()
     if banner is None:
         if err is None:
             err = '[exception] did not receive banner.'
@@ -1207,7 +1161,7 @@ def audit(out: OutputBuffer, aconf: AuditConf, sshv: Optional[int] = None, print
     if err is None:
         s.send_kexinit()  # Send the algorithms we support (except we don't since this isn't a real SSH connection).
 
-        packet_type, payload = s.read_packet(sshv)
+        packet_type, payload = s.read_packet()
         if packet_type < 0:
             try:
                 if len(payload) > 0:
@@ -1216,17 +1170,10 @@ def audit(out: OutputBuffer, aconf: AuditConf, sshv: Optional[int] = None, print
                     payload_txt = 'empty'
             except UnicodeDecodeError:
                 payload_txt = '"{}"'.format(repr(payload).lstrip('b')[1:-1])
-            if payload_txt == 'Protocol major versions differ.':
-                if sshv == 2 and aconf.ssh1:
-                    ret = audit(out, aconf, 1)
-                    out.write()
-                    return ret
             err = '[exception] error reading packet ({})'.format(payload_txt)
         else:
             err_pair = None
-            if sshv == 1 and packet_type != Protocol.SMSG_PUBLIC_KEY:
+            if packet_type != Protocol.MSG_KEXINIT:
-                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}), ' + \
@@ -1236,52 +1183,50 @@ def audit(out: OutputBuffer, aconf: AuditConf, sshv: Optional[int] = None, print
         output(out, aconf, banner, header)
         out.fail(err)
         return exitcodes.CONNECTION_ERROR
-    if sshv == 1:
-        program_retval = output(out, aconf, banner, header, pkm=SSH1_PublicKeyMessage.parse(payload))
-    elif sshv == 2:
-        try:
-            kex = SSH2_Kex.parse(out, payload)
-            out.d(str(kex))
-        except Exception:
-            out.fail("Failed to parse server's kex.  Stack trace:\n%s" % str(traceback.format_exc()))
-            return exitcodes.CONNECTION_ERROR
 
-        if aconf.dheat is not None:
+    try:
-            DHEat(out, aconf, banner, kex).run()
+        kex = SSH2_Kex.parse(out, payload)
-            return exitcodes.GOOD
+        out.d(str(kex))
-        elif aconf.conn_rate_test_enabled:
+    except Exception:
-            DHEat.dh_rate_test(out, aconf, kex, 0, 0, 0)
+        out.fail("Failed to parse server's kex.  Stack trace:\n%s" % str(traceback.format_exc()))
-            return exitcodes.GOOD
+        return exitcodes.CONNECTION_ERROR
 
-        dh_rate_test_notes = ""
+    if aconf.dheat is not None:
-        if aconf.client_audit is False:
+        DHEat(out, aconf, banner, kex).run()
-            HostKeyTest.run(out, s, kex)
+        return exitcodes.GOOD
-            if aconf.gex_test != '':
+    elif aconf.conn_rate_test_enabled:
-                return run_gex_granular_modulus_size_test(out, s, kex, aconf)
+        DHEat.dh_rate_test(out, aconf, kex, 0, 0, 0)
-            else:
+        return exitcodes.GOOD
-                GEXTest.run(out, s, banner, kex)
-
-                # Skip the rate test if the user specified "--skip-rate-test".
-                if aconf.skip_rate_test:
-                    out.d("Skipping rate test due to --skip-rate-test option.")
-                else:
-                    # Try to open many TCP connections against the server if any Diffie-Hellman key exchanges are present; this tests potential vulnerability to the DHEat DOS attack.  Use 3 concurrent sockets over at most 1.5 seconds to open at most 38 connections (stops if 1.5 seconds elapse, or 38 connections are opened--whichever comes first).  If more than 25 connections per second were observed, flag the DH algorithms with a warning about the DHEat DOS vuln.
-                    dh_rate_test_notes = DHEat.dh_rate_test(out, aconf, kex, 1.5, 38, 3)
-
-        # This is a standard audit scan.
-        if (aconf.policy is None) and (aconf.make_policy is False):
-            program_retval = output(out, aconf, banner, header, client_host=s.client_host, kex=kex, print_target=print_target, dh_rate_test_notes=dh_rate_test_notes)
-
-        # This is a policy test.
-        elif (aconf.policy is not None) and (aconf.make_policy is False):
-            program_retval = exitcodes.GOOD if evaluate_policy(out, 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)
 
+    dh_rate_test_notes = ""
+    if aconf.client_audit is False:
+        HostKeyTest.run(out, s, kex)
+        if aconf.gex_test != '':
+            return run_gex_granular_modulus_size_test(out, s, kex, aconf)
         else:
-            raise RuntimeError('Internal error while handling output: %r %r' % (aconf.policy is None, aconf.make_policy))
+            GEXTest.run(out, s, banner, kex)
+
+            # Skip the rate test if the user specified "--skip-rate-test".
+            if aconf.skip_rate_test:
+                out.d("Skipping rate test due to --skip-rate-test option.")
+            else:
+                # Try to open many TCP connections against the server if any Diffie-Hellman key exchanges are present; this tests potential vulnerability to the DHEat DOS attack.  Use 3 concurrent sockets over at most 1.5 seconds to open at most 38 connections (stops if 1.5 seconds elapse, or 38 connections are opened--whichever comes first).  If more than 25 connections per second were observed, flag the DH algorithms with a warning about the DHEat DOS vuln.
+                dh_rate_test_notes = DHEat.dh_rate_test(out, aconf, kex, 1.5, 38, 3)
+
+    # This is a standard audit scan.
+    if (aconf.policy is None) and (aconf.make_policy is False):
+        program_retval = output(out, aconf, banner, header, client_host=s.client_host, kex=kex, print_target=print_target, dh_rate_test_notes=dh_rate_test_notes)
+
+    # This is a policy test.
+    elif (aconf.policy is not None) and (aconf.make_policy is False):
+        program_retval = exitcodes.GOOD if evaluate_policy(out, 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
 
@@ -1548,7 +1493,6 @@ def main() -> int:
             print(']')
 
         # Send notification that this thread is exiting.  This deletes the thread's local copy of the algorithm databases.
-        SSH1_KexDB.thread_exit()
         SSH2_KexDB.thread_exit()
 
     else:  # Just a scan against a single target.

src/ssh_audit/ssh_socket.py

@@ -1,7 +1,7 @@
 """
    The MIT License (MIT)
 
-   Copyright (C) 2017-2021 Joe Testa (jtesta@positronsecurity.com)
+   Copyright (C) 2017-2025 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
@@ -39,7 +39,6 @@ from ssh_audit.globals import SSH_HEADER
 from ssh_audit.outputbuffer import OutputBuffer
 from ssh_audit.protocol import Protocol
 from ssh_audit.readbuf import ReadBuf
-from ssh_audit.ssh1 import SSH1
 from ssh_audit.ssh2_kex import SSH2_Kex
 from ssh_audit.ssh2_kexparty import SSH2_KexParty
 from ssh_audit.utils import Utils
@@ -173,7 +172,7 @@ class SSH_Socket(ReadBuf, WriteBuf):
             errm = 'cannot connect to {} port {}: {}'.format(*errt)
         return '[exception] {}'.format(errm)
 
-    def get_banner(self, sshv: int = 2) -> Tuple[Optional['Banner'], List[str], Optional[str]]:
+    def get_banner(self) -> Tuple[Optional['Banner'], List[str], Optional[str]]:
         self.__outputbuffer.d('Getting banner...', write_now=True)
 
         if self.__sock is None:
@@ -181,7 +180,7 @@ class SSH_Socket(ReadBuf, WriteBuf):
         if self.__banner is not None:
             return self.__banner, self.__header, None
 
-        banner = SSH_HEADER.format('1.5' if sshv == 1 else '2.0')
+        banner = SSH_HEADER.format('2.0')
         if self.__state < self.SM_BANNER_SENT:
             self.send_banner(banner)
 
@@ -254,47 +253,27 @@ class SSH_Socket(ReadBuf, WriteBuf):
             if s < 0:
                 raise SSH_Socket.InsufficientReadException(e)
 
-    def read_packet(self, sshv: int = 2) -> Tuple[int, bytes]:
+    def read_packet(self) -> Tuple[int, bytes]:
         try:
             header = WriteBuf()
             self.ensure_read(4)
             packet_length = self.read_int()
             header.write_int(packet_length)
             # XXX: validate length
-            if sshv == 1:
+            self.ensure_read(1)
-                padding_length = 8 - packet_length % 8
+            padding_length = self.read_byte()
-                self.ensure_read(padding_length)
+            header.write_byte(padding_length)
-                padding = self.read(padding_length)
+            payload_length = packet_length - padding_length - 1
-                header.write(padding)
+            check_size = 4 + 1 + payload_length + padding_length
-                payload_length = packet_length
-                check_size = padding_length + payload_length
-            else:
-                self.ensure_read(1)
-                padding_length = self.read_byte()
-                header.write_byte(padding_length)
-                payload_length = packet_length - padding_length - 1
-                check_size = 4 + 1 + payload_length + padding_length
             if check_size % self.__block_size != 0:
                 self.__outputbuffer.fail('[exception] invalid ssh packet (block size)').write()
                 sys.exit(exitcodes.CONNECTION_ERROR)
             self.ensure_read(payload_length)
-            if sshv == 1:
+            payload = self.read(payload_length)
-                payload = self.read(payload_length - 4)
+            header.write(payload)
-                header.write(payload)
-                crc = self.read_int()
-                header.write_int(crc)
-            else:
-                payload = self.read(payload_length)
-                header.write(payload)
             packet_type = ord(payload[0:1])
-            if sshv == 1:
+            self.ensure_read(padding_length)
-                rcrc = SSH1.crc32(padding + payload)
+            _ = self.read(padding_length)
-                if crc != rcrc:
-                    self.__outputbuffer.fail('[exception] packet checksum CRC32 mismatch.').write()
-                    sys.exit(exitcodes.CONNECTION_ERROR)
-            else:
-                self.ensure_read(padding_length)
-                padding = self.read(padding_length)
             payload = payload[1:]
             return packet_type, payload
         except SSH_Socket.InsufficientReadException as ex:

ssh-audit.1

@@ -1,4 +1,4 @@
-.TH SSH-AUDIT 1 "September 24, 2024"
+.TH SSH-AUDIT 1 "July 26, 2025"
 .SH NAME
 \fBssh-audit\fP \- SSH server & client configuration auditor
 .SH SYNOPSIS
@@ -16,16 +16,6 @@ See <https://www.ssh\-audit.com/> for official hardening guides for common platf
 .br
 Print short summary of options.
 
-.TP
-.B -1, \-\-ssh1
-.br
-Only perform an audit using SSH protocol version 1.
-
-.TP
-.B -2, \-\-ssh2
-.br
-Only perform an audit using SSH protocol version 2.
-
 .TP
 .B -4, \-\-ipv4
 .br

test/test_auditconf.py

@@ -15,8 +15,6 @@ class TestAuditConf:
         options = {
             'host': '',
             'port': 22,
-            'ssh1': True,
-            'ssh2': True,
             'batch': False,
             'colors': True,
             'verbose': False,
@@ -28,8 +26,6 @@ class TestAuditConf:
             options[k] = v
         assert conf.host == options['host']
         assert conf.port == options['port']
-        assert conf.ssh1 is options['ssh1']
-        assert conf.ssh2 is options['ssh2']
         assert conf.batch is options['batch']
         assert conf.colors is options['colors']
         assert conf.verbose is options['verbose']
@@ -43,7 +39,7 @@ class TestAuditConf:
 
     def test_audit_conf_booleans(self):
         conf = self.AuditConf()
-        for p in ['ssh1', 'ssh2', 'batch', 'colors', 'verbose']:
+        for p in ['batch', 'colors', 'verbose']:
             for v in [True, 1]:
                 setattr(conf, p, v)
                 assert getattr(conf, p) is True
@@ -147,12 +143,6 @@ class TestAuditConf:
             conf = c('localhost:99999')
         with pytest.raises(SystemExit):
             conf = c('-p 99999 localhost')
-        conf = c('-1 localhost')
-        self._test_conf(conf, host='localhost', ssh1=True, ssh2=False)
-        conf = c('-2 localhost')
-        self._test_conf(conf, host='localhost', ssh1=False, ssh2=True)
-        conf = c('-12 localhost')
-        self._test_conf(conf, host='localhost', ssh1=True, ssh2=True)
         conf = c('-4 localhost')
         self._test_conf(conf, host='localhost', ipv4=True, ipv6=False, ipvo=(4,))
         conf = c('-6 localhost')

test/test_errors.py

@@ -166,7 +166,6 @@ class TestErrors:
         vsocket.rdata.append(b'SSH-1.3-ssh-audit-test\r\n')
         vsocket.rdata.append(b'Protocol major versions differ.\n')
         conf = self._conf()
-        conf.ssh1, conf.ssh2 = True, False
         lines = self._audit(output_spy, conf)
         assert len(lines) == 4
         assert 'error reading packet' in lines[-1]

test/test_ssh1.py

@@ -1,174 +0,0 @@
-import struct
-import pytest
-
-from ssh_audit.auditconf import AuditConf
-from ssh_audit.fingerprint import Fingerprint
-from ssh_audit.outputbuffer import OutputBuffer
-from ssh_audit.protocol import Protocol
-from ssh_audit.readbuf import ReadBuf
-from ssh_audit.ssh1 import SSH1
-from ssh_audit.ssh1_publickeymessage import SSH1_PublicKeyMessage
-from ssh_audit.ssh_audit import audit
-from ssh_audit.writebuf import WriteBuf
-
-
-# pylint: disable=line-too-long,attribute-defined-outside-init
-class TestSSH1:
-    @pytest.fixture(autouse=True)
-    def init(self, ssh_audit):
-        self.OutputBuffer = OutputBuffer
-        self.protocol = Protocol
-        self.ssh1 = SSH1
-        self.PublicKeyMessage = SSH1_PublicKeyMessage
-        self.rbuf = ReadBuf
-        self.wbuf = WriteBuf
-        self.audit = audit
-        self.AuditConf = AuditConf
-        self.fingerprint = Fingerprint
-
-    def _conf(self):
-        conf = self.AuditConf('localhost', 22)
-        conf.colors = False
-        conf.batch = True
-        conf.verbose = True
-        conf.ssh1 = True
-        conf.ssh2 = False
-        conf.skip_rate_test = True
-        return conf
-
-    def _create_ssh1_packet(self, payload, valid_crc=True):
-        padding = -(len(payload) + 4) % 8
-        plen = len(payload) + 4
-        pad_bytes = b'\x00' * padding
-        cksum = self.ssh1.crc32(pad_bytes + payload) if valid_crc else 0
-        data = struct.pack('>I', plen) + pad_bytes + payload + struct.pack('>I', cksum)
-        return data
-
-    @classmethod
-    def _server_key(cls):
-        return (1024, 0x10001, 0xee6552da432e0ac2c422df1a51287507748bfe3b5e3e4fa989a8f49fdc163a17754939ef18ef8a667ea3b71036a151fcd7f5e01ceef1e4439864baf3ac569047582c69d6c128212e0980dcb3168f00d371004039983f6033cd785b8b8f85096c7d9405cbfdc664e27c966356a6b4eb6ee20ad43414b50de18b22829c1880b551)
-
-    @classmethod
-    def _host_key(cls):
-        return (2048, 0x10001, 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)
-
-    def _pkm_payload(self):
-        w = self.wbuf()
-        w.write(b'\x88\x99\xaa\xbb\xcc\xdd\xee\xff')
-        b, e, m = self._server_key()
-        w.write_int(b).write_mpint1(e).write_mpint1(m)
-        b, e, m = self._host_key()
-        w.write_int(b).write_mpint1(e).write_mpint1(m)
-        w.write_int(2)
-        w.write_int(72)
-        w.write_int(36)
-        return w.write_flush()
-
-    def test_crc32(self):
-        assert self.ssh1.crc32(b'') == 0x00
-        assert self.ssh1.crc32(b'The quick brown fox jumps over the lazy dog') == 0xb9c60808
-
-    def test_fingerprint(self):
-        # pylint: disable=protected-access
-        b, e, m = self._host_key()
-        fpd = self.wbuf._create_mpint(m, False)
-        fpd += self.wbuf._create_mpint(e, False)
-        fp = self.fingerprint(fpd)
-        assert b == 2048
-        assert fp.md5 == 'MD5:9d:26:f8:39:fc:20:9d:9b:ca:cc:4a:0f:e1:93:f5:96'
-        assert fp.sha256 == 'SHA256:vZdx3mhzbvVJmn08t/ruv8WDhJ9jfKYsCTuSzot+QIs'
-
-    def _assert_pkm_keys(self, pkm, skey, hkey):
-        b, e, m = skey
-        assert pkm.server_key_bits == b
-        assert pkm.server_key_public_exponent == e
-        assert pkm.server_key_public_modulus == m
-        b, e, m = hkey
-        assert pkm.host_key_bits == b
-        assert pkm.host_key_public_exponent == e
-        assert pkm.host_key_public_modulus == m
-
-    def _assert_pkm_fields(self, pkm, skey, hkey):
-        assert pkm is not None
-        assert pkm.cookie == b'\x88\x99\xaa\xbb\xcc\xdd\xee\xff'
-        self._assert_pkm_keys(pkm, skey, hkey)
-        assert pkm.protocol_flags == 2
-        assert pkm.supported_ciphers_mask == 72
-        assert pkm.supported_ciphers == ['3des', 'blowfish']
-        assert pkm.supported_authentications_mask == 36
-        assert pkm.supported_authentications == ['rsa', 'tis']
-        fp = self.fingerprint(pkm.host_key_fingerprint_data)
-        assert fp.md5 == 'MD5:9d:26:f8:39:fc:20:9d:9b:ca:cc:4a:0f:e1:93:f5:96'
-        assert fp.sha256 == 'SHA256:vZdx3mhzbvVJmn08t/ruv8WDhJ9jfKYsCTuSzot+QIs'
-
-    def test_pkm_init(self):
-        cookie = b'\x88\x99\xaa\xbb\xcc\xdd\xee\xff'
-        pflags, cmask, amask = 2, 72, 36
-        skey, hkey = self._server_key(), self._host_key()
-        pkm = self.PublicKeyMessage(cookie, skey, hkey, pflags, cmask, amask)
-        self._assert_pkm_fields(pkm, skey, hkey)
-        for skey2 in ([], [0], [0, 1], [0, 1, 2, 3]):
-            with pytest.raises(ValueError):
-                pkm = self.PublicKeyMessage(cookie, skey2, hkey, pflags, cmask, amask)
-        for hkey2 in ([], [0], [0, 1], [0, 1, 2, 3]):
-            with pytest.raises(ValueError):
-                print(hkey2)
-                pkm = self.PublicKeyMessage(cookie, skey, hkey2, pflags, cmask, amask)
-
-    def test_pkm_read(self):
-        pkm = self.PublicKeyMessage.parse(self._pkm_payload())
-        self._assert_pkm_fields(pkm, self._server_key(), self._host_key())
-
-    def test_pkm_payload(self):
-        cookie = b'\x88\x99\xaa\xbb\xcc\xdd\xee\xff'
-        skey, hkey = self._server_key(), self._host_key()
-        pflags, cmask, amask = 2, 72, 36
-        pkm1 = self.PublicKeyMessage(cookie, skey, hkey, pflags, cmask, amask)
-        pkm2 = self.PublicKeyMessage.parse(self._pkm_payload())
-        assert pkm1.payload == pkm2.payload
-
-    def test_ssh1_server_simple(self, output_spy, virtual_socket):
-        vsocket = virtual_socket
-        w = self.wbuf()
-        w.write_byte(self.protocol.SMSG_PUBLIC_KEY)
-        w.write(self._pkm_payload())
-        vsocket.rdata.append(b'SSH-1.5-OpenSSH_7.2 ssh-audit-test\r\n')
-        vsocket.rdata.append(self._create_ssh1_packet(w.write_flush()))
-        output_spy.begin()
-        out = self.OutputBuffer()
-        self.audit(out, self._conf())
-        out.write()
-        lines = output_spy.flush()
-        assert len(lines) == 13
-
-    def test_ssh1_server_invalid_first_packet(self, output_spy, virtual_socket):
-        vsocket = virtual_socket
-        w = self.wbuf()
-        w.write_byte(self.protocol.SMSG_PUBLIC_KEY + 1)
-        w.write(self._pkm_payload())
-        vsocket.rdata.append(b'SSH-1.5-OpenSSH_7.2 ssh-audit-test\r\n')
-        vsocket.rdata.append(self._create_ssh1_packet(w.write_flush()))
-        output_spy.begin()
-        out = self.OutputBuffer()
-        ret = self.audit(out, self._conf())
-        out.write()
-        assert ret != 0
-        lines = output_spy.flush()
-        assert len(lines) == 6
-        assert 'unknown message' in lines[-1]
-
-    def test_ssh1_server_invalid_checksum(self, output_spy, virtual_socket):
-        vsocket = virtual_socket
-        w = self.wbuf()
-        w.write_byte(self.protocol.SMSG_PUBLIC_KEY + 1)
-        w.write(self._pkm_payload())
-        vsocket.rdata.append(b'SSH-1.5-OpenSSH_7.2 ssh-audit-test\r\n')
-        vsocket.rdata.append(self._create_ssh1_packet(w.write_flush(), False))
-        output_spy.begin()
-        out = self.OutputBuffer()
-        with pytest.raises(SystemExit):
-            self.audit(out, self._conf())
-        out.write()
-        lines = output_spy.flush()
-        assert len(lines) == 3
-        assert ('checksum' in lines[0]) or ('checksum' in lines[1]) or ('checksum' in lines[2])