I'm contemplating whether it would be possible make the man page available in Windows.

This is not a complete solution, these are just my initial thoughts exploring what would be required and how we might go about doing it... Any thoughts, feedback or suggestions would be welcome...

Converting the man page to a readable format for the Windows console

Since Windows doesn't have a manual reader, the man page would need to be converted to a format that can be rendered in the Windows console. This would have to be performed as part of the build process when there's a new release.

One option would be to simply convert it to plain text output. This conversion can be achieved as follows:

MANWIDTH=80 man ./ssh-audit.1 > ssh_audit_windows_man.txt

In Windows 10, the console is capable of interpreting ANSI escape sequences (also known as VT escape sequences). So another option would be to convert the man page to ANSI escape sequence formatted output, this would preserve any typographical emphasis that's present in the original man page, such as bold and underlined text. This conversion can be achieved as follows:

# * man outputs a backspace-overwrite sequence rather than an ANSI escape 
#   sequence.
# * 'MAN_KEEP_FORMATTING' preserves the backspace-overwrite sequence when 
#   redirected to a file or a pipe.
# * The 'ul' command converts the backspace-overwrite sequence to an ANSI escape 
#   sequence.

MANWIDTH=80 MAN_KEEP_FORMATTING=1 man ./ssh-audit.1 | ul > ssh_audit_windows_man.txt

Example of an ANSI escape sequence formatted man page on Windows 10

import os
os.system("color")

f = open('c:\\bitbucket\\ssh_audit_windows_man.txt', encoding="utf-8")
file_contents = f.read()
print (file_contents)
f.close()

Displaying the man page

Displaying the man page could perhaps be invoked using a command line parameter such as:

ssh-audit.exe --manual

Packaging the converted man page

Currently the Windows package is a standalone executable with no external dependencies. Ideally any solution that's adopted would preserve this.

Does anyone know of a way that the man page (in its converted format) could be embedded into the ssh-audit executable without having to ship an external text file?

I've encountered an SSH server where the Diffie-Hellman group size used by the key exchange algorithm diffie-hellman-group-exchange-sha256 is hardcoded and cannot be seen or configured by an administrator.

My plan was to use ssh-audit to scan the server and find out more information about the supported group size(s) but then I realised that ssh-audit only returns the minimum value.

I studied RFC 4419 which explains how the client requests a modulus from the server by specifying a minimum, a preferred and a maximum value (expressed in bits). The send_init_gex function in ssh-audit has been implemented as per the explanation in RFC 4419, it accepts minbits, prefbits and maxbits.

I was able to modify gextest.py to invoke send_init_gex with minbits, prefbits and maxbits of the same value from 0 to 8192. This gave me the answer I was looking for, it showed that the server was configured with group sizes of 1024, 2048, 3072, 4096 and 6144. Using this information I can now contact the manufacturer of the SSH server software and ask if they will consider removing 1024.

@jtesta What do you think about about adding group size enumeration as a feature to ssh-audit? I could submit my patch as a draft for you to review?

Enumerating every value from 0 to 8192 is a slow process because it has to make a new connection to the target server each time. In my case this was not a problem because I ran the patched version of ssh-audit on the SSH server itself. However, if someone were to attempt this over a network it may cause a firewall's rate control to be triggered resulting in requests being blocked. So we'd probably need to mention this as a potential caveat in the documentation.

When when verifying host keys, PuTTY, plink and psftp use an md5 hash rather than a sha256 hash.

C:\sandbox>plink.exe -v scanme.nmap.org
Looking up host "scanme.nmap.org" for SSH connection
Connecting to 45.33.32.156 port 22
We claim version: SSH-2.0-PuTTY_Release_0.74
Remote version: SSH-2.0-OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.13
We believe remote version has SSH-2 channel request bug
Using SSH protocol version 2
No GSSAPI security context available
Doing ECDH key exchange with curve Curve25519 and hash SHA-256 (unaccelerated)
Server also has ecdsa-sha2-nistp256/ssh-dss/ssh-rsa host keys, but we don't know any of them
Host key fingerprint is:
ssh-ed25519 255 33:fa:91:0f:e0:e1:7b:1f:6d:05:a2:b0:f1:54:41:56
The server's host key is not cached in the registry. You
have no guarantee that the server is the computer you
think it is.
The server's ssh-ed25519 key fingerprint is:
ssh-ed25519 255 33:fa:91:0f:e0:e1:7b:1f:6d:05:a2:b0:f1:54:41:56
If you trust this host, enter "y" to add the key to
PuTTY's cache and carry on connecting.
If you want to carry on connecting just once, without
adding the key to the cache, enter "n".
If you do not trust this host, press Return to abandon the
connection.
Store key in cache? (y/n) 

Currently ssh-audit only shows fingerprints in the form of a sha256 hash. Do you have any objection to also showing the md5 hash if the verbose (-v/--verbose) parameter has been provided?

I've built a proof-of-concept that I can share.

By the way, the Fingerprint class is already capable of producing an md5 hash, it's just not currently used: https://github.com/jtesta/ssh-audit/blob/2f1a2a60b153509612a450173041fb698177dc45/src/ssh_audit/fingerprint.py#L33-L37

Hi @jtesta

I just discovered the client hardening mode.

I run Ubuntu 18.04 on my laptop.

I applied the changes from your hardening guide

https://www.ssh-audit.com/hardening_guides.html#ubuntu_18_04_linux_mint_19

and then I started the client audit via python3.8 ssh-audit.py -c and then on a second terminal, I sshed into localhost port 2222.

Expected I expected all output to be green.

what I got

# general
(gen) client IP: 127.0.0.1
(gen) banner: SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
(gen) software: OpenSSH 7.6p1
(gen) compression: enabled ([email protected], zlib)

# key exchange algorithms
(kex) curve25519-sha256                         -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
(kex) [email protected]              -- [info] available since OpenSSH 6.5, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp256                        -- [fail] using weak elliptic curves
                                                `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp384                        -- [fail] using weak elliptic curves
                                                `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp521                        -- [fail] using weak elliptic curves
                                                `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) diffie-hellman-group-exchange-sha256      -- [info] available since OpenSSH 4.4
(kex) diffie-hellman-group16-sha512             -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
(kex) diffie-hellman-group18-sha512             -- [info] available since OpenSSH 7.3
(kex) diffie-hellman-group-exchange-sha1        -- [fail] removed (in server) since OpenSSH 6.7, unsafe algorithm
                                                `- [warn] using weak hashing algorithm
                                                `- [info] available since OpenSSH 2.3.0
(kex) diffie-hellman-group14-sha256             -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
(kex) diffie-hellman-group14-sha1               -- [warn] using weak hashing algorithm
                                                `- [info] available since OpenSSH 3.9, Dropbear SSH 0.53
(kex) ext-info-c

# host-key algorithms
(key) [email protected]  -- [fail] using weak elliptic curves
                                                `- [warn] using weak random number generator could reveal the key
                                                `- [info] available since OpenSSH 5.7
(key) [email protected]  -- [fail] using weak elliptic curves
                                                `- [warn] using weak random number generator could reveal the key
                                                `- [info] available since OpenSSH 5.7
(key) [email protected]  -- [fail] using weak elliptic curves
                                                `- [warn] using weak random number generator could reveal the key
                                                `- [info] available since OpenSSH 5.7
(key) [email protected]          -- [info] available since OpenSSH 6.5
(key) [email protected]              -- [info] available since OpenSSH 5.6
(key) ecdsa-sha2-nistp256                       -- [fail] using weak elliptic curves
                                                `- [warn] using weak random number generator could reveal the key
                                                `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(key) ecdsa-sha2-nistp384                       -- [fail] using weak elliptic curves
                                                `- [warn] using weak random number generator could reveal the key
                                                `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(key) ecdsa-sha2-nistp521                       -- [fail] using weak elliptic curves
                                                `- [warn] using weak random number generator could reveal the key
                                                `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(key) ssh-ed25519                               -- [info] available since OpenSSH 6.5
(key) rsa-sha2-512                              -- [info] available since OpenSSH 7.2
(key) rsa-sha2-256                              -- [info] available since OpenSSH 7.2
(key) ssh-rsa                                   -- [fail] using weak hashing algorithm
                                                `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28

# encryption algorithms (ciphers)
(enc) [email protected]             -- [info] available since OpenSSH 6.5
                                                `- [info] default cipher since OpenSSH 6.9.
(enc) aes128-ctr                                -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
(enc) aes192-ctr                                -- [info] available since OpenSSH 3.7
(enc) aes256-ctr                                -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
(enc) [email protected]                    -- [info] available since OpenSSH 6.2
(enc) [email protected]                    -- [info] available since OpenSSH 6.2

# message authentication code algorithms
(mac) [email protected]                   -- [warn] using small 64-bit tag size
                                                `- [info] available since OpenSSH 6.2
(mac) [email protected]                  -- [info] available since OpenSSH 6.2
(mac) [email protected]             -- [info] available since OpenSSH 6.2
(mac) [email protected]             -- [info] available since OpenSSH 6.2
(mac) [email protected]                 -- [warn] using weak hashing algorithm
                                                `- [info] available since OpenSSH 6.2
(mac) [email protected]                       -- [warn] using encrypt-and-MAC mode
                                                `- [warn] using small 64-bit tag size
                                                `- [info] available since OpenSSH 4.7
(mac) [email protected]                      -- [warn] using encrypt-and-MAC mode
                                                `- [info] available since OpenSSH 6.2
(mac) hmac-sha2-256                             -- [warn] using encrypt-and-MAC mode
                                                `- [info] available since OpenSSH 5.9, Dropbear SSH 2013.56
(mac) hmac-sha2-512                             -- [warn] using encrypt-and-MAC mode
                                                `- [info] available since OpenSSH 5.9, Dropbear SSH 2013.56
(mac) hmac-sha1                                 -- [warn] using encrypt-and-MAC mode
                                                `- [warn] using weak hashing algorithm
                                                `- [info] available since OpenSSH 2.1.0, Dropbear SSH 0.28

# algorithm recommendations (for OpenSSH 7.6)
(rec) -diffie-hellman-group-exchange-sha1       -- kex algorithm to remove 
(rec) -ecdh-sha2-nistp256                       -- kex algorithm to remove 
(rec) -ecdh-sha2-nistp384                       -- kex algorithm to remove 
(rec) -ecdh-sha2-nistp521                       -- kex algorithm to remove 
(rec) -ecdsa-sha2-nistp256                      -- key algorithm to remove 
(rec) [email protected] -- key algorithm to remove 
(rec) -ecdsa-sha2-nistp384                      -- key algorithm to remove 
(rec) [email protected] -- key algorithm to remove 
(rec) -ecdsa-sha2-nistp521                      -- key algorithm to remove 
(rec) [email protected] -- key algorithm to remove 
(rec) -ssh-rsa                                  -- key algorithm to remove 
(rec) -diffie-hellman-group14-sha1              -- kex algorithm to remove 
(rec) -hmac-sha1                                -- mac algorithm to remove 
(rec) [email protected]                -- mac algorithm to remove 
(rec) -hmac-sha2-256                            -- mac algorithm to remove 
(rec) -hmac-sha2-512                            -- mac algorithm to remove 
(rec) [email protected]                     -- mac algorithm to remove 
(rec) [email protected]                  -- mac algorithm to remove 
(rec) [email protected]                      -- mac algorithm to remove 

# additional info
(nfo) For hardening guides on common OSes, please see: <https://www.ssh-audit.com/hardening_guides.html>

My ssh config contains some jumphost configurtations, and then on the bottom your suggested changes which I echoed into the file.

# lots of hosts...

Host xxx
    Hostname 192.168.1.220
    ProxyJump yyy

Ciphers [email protected],[email protected],[email protected],aes256-ctr,aes192-ctr,aes128-ctr
KexAlgorithms curve25519-sha256,[email protected],diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha256
MACs [email protected],[email protected],[email protected]
HostKeyAlgorithms ssh-ed25519,[email protected],rsa-sha2-256,rsa-sha2-512,[email protected]

I tried to google about client hardening, but almost all information out there is about server hardening.

Any hint for me what to do?

Thanks!

Hi Joe,

The tool currently suggests recommended settings for OpenSSH 7.6 but I currently have OpenSSH_8.0p1, OpenSSL 1.1.1c 28 May 2019, so it would be great to have up-to-date kex/mac/etc recommendations what to enable, disable, and so on. There might be such in the official docs but the tool should make it easy to find them via its output.

# algorithm recommendations (for OpenSSH 7.6)
...

It would be convenient if host entries in .ssh/config (hostname, port) could be recognised and automatically be used, so an entry like

Host staging
	PubkeyAuthentication yes
	IdentitiesOnly yes
	IdentityFile ~/.ssh/id_ed25519
	Hostname mystagingserver.domain.com
	User dummy
	Port 54321

would allow a simple

ssh-audit.py staging

instead of a

ssh-audit.py -p 54321 mystagingserver.domain.com

Hi @jtesta,

According to https://github.com/opnsense/core/issues/3975, there will be new SSH config options in OPNsense 20.7, so it'd be great to add these to the common OS list at https://www.ssh-audit.com/hardening_guides.html maybe below pfSense (as OPNsense is its fork).

Until the new settings are released, users can enable them by running these commands on their OPNsense box/vm:

opnsense-patch 5df590c
opnsense-patch 1165119
service configd restart

As there are no ordering in the chosen algos (limitation of the UI), advanced users that mess with these settings should pick their choices to be the most hard that their SSH clients support. I'm happy that they added support to tweaking these at least.

@jtesta Hi Joe,

At the end of July you mentioned that you were hoping to release v2.3.0.

Are there some specific issues that you want to close before releasing v2.3.0? If so, perhaps they could be tagged as milestones.

ADDITIONAL LOGGING

I'm planning on using ssh-audit in a production environment and would like to be able to demonstrate and record how aggressive a typical audit is.

Currently verbose output only shows the initial SSH connection that's made to a target server:

https://github.com/jtesta/ssh-audit/blob/c483fe1861bcfaefabec21a9195b7c226540aaa4/src/ssh_audit/ssh_audit.py#L823

However an audit actually makes multiple connections to a target server:

1. The initial connection:
   ssh_audit.py: main --> audit --> err = s.connect()

2. Obtaining host key(s):
   ssh_audit.py: main --> audit --> HostKeyTest.run(s, kex) hostkeytest.py: run --> perform_test --> err = s.connect() (err = s.connect() runs once per key type [rsa, ed25519, etc])

3. Performing DH group exchange: ssh_audit.py: main --> audit --> GEXTest.run(s, kex) gextest.py: run --> GEXTest.reconnect --> err = s.connect() (GEXTest.reconnect runs once per group-exchange alg and once per modulus length for each group-exchange alg)

@jtesta Would you be happy to entertain the idea of adding some additional logging so that each SSH connection is output? If that sounds OK, do you want this to be added to the existing verbose output or would it be more appropriate to add a new --debug parameter?

VISIBILITY OF ERRORS

When obtaining host key(s) and performing DH group exchange, if s.connect() or get_banner() produce an error then currently the error message is suppressed:

https://github.com/jtesta/ssh-audit/blob/c483fe1861bcfaefabec21a9195b7c226540aaa4/src/ssh_audit/hostkeytest.py#L109-L116

https://github.com/jtesta/ssh-audit/blob/c483fe1861bcfaefabec21a9195b7c226540aaa4/src/ssh_audit/gextest.py#L45-L52

Should we at least display a warning rather than hiding errors?

@jtesta Hi Joe

The OpenSSH 8.3 release notes includes a future deprecation notice where it says: "...we will be disabling the "ssh-rsa" public key signature algorithm by default in a near-future release".

Is it worth updating ssh-rsa in ssh2_kexdb.py to mention something like "A future deprecation notice has been issued in OpenSSH 8.3, see https://www.openssh.com/txt/release-8.3." ?

When I researched the deprecation of ssh-rsa, there seems to be a degree of confusion about the whole thing. So before you do anything, it's probably a good idea to check and make sure that you agree with my interpretation and that I'm not perpetuating incorrect information.

Hello,

When i try to scan a batch of targets in a file if one of those get a [exception] cannot connect to 127.0.0.1 port 22 : timed out or connection refused the scan fails. i tried specifying the -b flag but that did not help much. The work around was to just cat the file and run it in parallel/xargs. But i still figured i should let you know.

The current release of dropbear can be hardened by building it adding the following three lines to localoptions.h:

#define DROPBEAR_RSA_SHA1 0
#define DROPBEAR_DH_GROUP14_SHA1 0
#define DROPBEAR_SHA1_HMAC 0

Wondering if you would like to add this to your hardening guide.

Reference: https://github.com/mkj/dropbear/issues/138

When scanning a remote server, only the sha256 fingerprints are shown.

It would make sense, to calculate the fingerprint with different hash algorithms, because not every client uses a sha256 hash for fingerprint calculation.

Following hash algorithms should be used:

• MD5 (deprecated but there are still clients which are using MD5)
• SHA512 (rarely used but some clients exist which are using SHA512 fingerprints)

I know those algorithms are not common, but as long as some clients are using those, ssh-audit should calculate the fingerprints.

I get an exception when scanning some targets using targets file. When scanning these targets manually, it works fine.

I'm using the ssh-audit.exe in Version 2.5 on a Windows 10 VM. For me it looks like to be an issue of missing import: import encodings.idna

An exception occurred while scanning 10.2xx.xx.xx:22: Traceback (most recent call last): File "ssh-audit.py", line 1017, in target_worker_thread File "ssh-audit.py", line 842, in audit File "ssh_socket.py", line 155, in connect File "ssh_socket.py", line 85, in _resolve File "socket.py", line 953, in getaddrinfo LookupError: unknown encoding: idna

An exception occurred while scanning 10.2xx.xxx.xx:22: Traceback (most recent call last): File "ssh-audit.py", line 1017, in target_worker_thread File "ssh-audit.py", line 842, in audit File "ssh_socket.py", line 155, in connect File "ssh_socket.py", line 85, in _resolve File "socket.py", line 953, in getaddrinfo LookupError: unknown encoding: idna

An exception occurred while scanning 10.2xx.xxx.xx:22: Traceback (most recent call last): File "ssh-audit.py", line 1017, in target_worker_thread File "ssh-audit.py", line 842, in audit File "ssh_socket.py", line 155, in connect File "ssh_socket.py", line 85, in _resolve File "socket.py", line 953, in getaddrinfo LookupError: unknown encoding: idna

An exception occurred while scanning 10.2xx.xx.xx:22: Traceback (most recent call last): File "ssh-audit.py", line 1017, in target_worker_thread File "ssh-audit.py", line 842, in audit File "ssh_socket.py", line 155, in connect File "ssh_socket.py", line 85, in _resolve File "socket.py", line 953, in getaddrinfo LookupError: unknown encoding: idna

An exception occurred while scanning 10.2xx.xxx.xx:22: Traceback (most recent call last): File "ssh-audit.py", line 1017, in target_worker_thread File "ssh-audit.py", line 842, in audit File "ssh_socket.py", line 155, in connect File "ssh_socket.py", line 85, in _resolve File "socket.py", line 953, in getaddrinfo LookupError: unknown encoding: idna

(output truncated)

$ pip3 show -f ssh-audit
Version: 2.5.0
License: UNKNOWN
Location: /usr/local/lib/python3.10/site-packages
Requires: 
Required-by: 
Files:
  ../../../bin/ssh-audit
  ssh_audit-2.5.0.dist-info/LICENSE

Hello. Be it unknown or not to Python, the license is dully mentioned here

$ cat /usr/local/lib/python3.10/site-packages/ssh_audit-2.5.0.dist-info/LICENSE | awk 'NF'| head -2
The MIT License (MIT)
Copyright (C) 2017-2020 Joe Testa ([email protected])

Whatever the side the issue has root, it is worth fixing. Copyright's end-year might require up-to-date number. Worth noting that an en-dash (–), is what the usage defines as applying to range of dates, not a hyphen (-), which is commonly misused by developers.

Hi!

I'm working on a product, that needs to implement ssh / scp themselves. I've read a dozens of rfc's myself already, but still would rather not implement everything myself. As such I've opted to use Apache Mina SSHD.

Trying to disable the ecdsa-sha2-nistp521 Signature however seems to be problematic. I can see, that ssh-audit tries connecting with only that signature algorithm and then see that the server implementation concludes, that a session cannot be negotiated properly. As such it sends the Message SSH_MSG_DISCONNECT (1), while logging the error message: "SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE - sendKexInit() no resolved signatures available".

However ssh-audit then fails to execute with the following message: [exception] did not receive MSG_KEXINIT (20), instead received unknown message (1). While reading the RFC 4253 i would say, that this is to be expected though, as on Page 18 it says:

  If no algorithm satisfying all these conditions can be found, the
  connection fails, and both sides MUST disconnect.

My Test Code utilizes Containers (testContainers-java) and JUnit. For reference:

import lombok.Cleanup;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.Test;
import org.testcontainers.containers.GenericContainer;
import org.testcontainers.containers.output.Slf4jLogConsumer;
import org.testcontainers.containers.startupcheck.IndefiniteWaitOneShotStartupCheckStrategy;
import org.testcontainers.junit.jupiter.Testcontainers;
import org.testcontainers.utility.MountableFile;

import java.io.IOException;

import static org.testcontainers.Testcontainers.exposeHostPorts;

@Slf4j
@Testcontainers
public final class SSHTest {
    private static final int SSH_PORT = 2222;


    @Test
    public void testAudit() throws Exception {
        @Cleanup final var launcher = createLauncher();
        launcher.start();

        exposeHostPorts(SSH_PORT);

        @Cleanup final var container = createContainerAudit();
        container.start();
    }

    private static GenericContainer<?> createContainerAudit() {
        return new SSHAudit(new SSHAudit.Config(SSH_URL, SSH_PORT))
            .withLogConsumer(new Slf4jLogConsumer(log))
            .withStartupCheckStrategy(new IndefiniteWaitOneShotStartupCheckStrategy());
    }
}

import org.testcontainers.containers.GenericContainer;
import org.testcontainers.utility.DockerImageName;

final class SSHAudit extends GenericContainer<SSHAudit> {
    public SSHAudit(final Config config) {
        super(DockerImageName.parse("positronsecurity/ssh-audit"));
        this.setCommand(
            "-b",
//            "-l", "warn",
            config.url()
        );
    }

    public record Config(
        String host,
        int port
    ) {
        String url() {
            return this.host + ":" + this.port;
        }
    }
}

The cause of the error is linked here

I'm unsure on how one would approach this though. As I have not yet understood the code base here. My suggestion would be to check if the server disconnected, but i can see. that the protocol definition currently has no such field.

EDIT:

[main] INFO 🐳 [positronsecurity/ssh-audit:latest] - Container positronsecurity/ssh-audit:latest started in PT1.5658137S

STDOUT # ssh-audit.py v2.5.0, https://github.com/jtesta/ssh-audit
STDOUT 
STDOUT usage: ssh-audit.py [options] <host>
STDOUT 
STDOUT    -h,  --help             print this help
STDOUT    -1,  --ssh1             force ssh version 1 only
STDOUT    -2,  --ssh2             force ssh version 2 only
STDOUT    -4,  --ipv4             enable IPv4 (order of precedence)
STDOUT    -6,  --ipv6             enable IPv6 (order of precedence)
STDOUT    -b,  --batch            batch output
STDOUT    -c,  --client-audit     starts a server on port 2222 to audit client
STDOUT                                software config (use -p to change port;
STDOUT                                use -t to change timeout)
STDOUT    -d,  --debug            debug output
STDOUT    -j,  --json             JSON output (use -jj to enable indents)
STDOUT    -l,  --level=<level>    minimum output level (info|warn|fail)
STDOUT    -L,  --list-policies    list all the official, built-in policies
STDOUT         --lookup=<alg1,alg2,...>    looks up an algorithm(s) without
STDOUT                                     connecting to a server
STDOUT    -M,  --make-policy=<policy.txt>  creates a policy based on the target server
STDOUT                                     (i.e.: the target server has the ideal
STDOUT                                     configuration that other servers should
STDOUT                                     adhere to)
STDOUT    -m,  --manual           print the man page (Windows only)
STDOUT    -n,  --no-colors        disable colors
STDOUT    -p,  --port=<port>      port to connect
STDOUT    -P,  --policy=<policy.txt>  run a policy test using the specified policy
STDOUT    -t,  --timeout=<secs>   timeout (in seconds) for connection and reading
STDOUT                                (default: 5)
STDOUT    -T,  --targets=<hosts.txt>  a file containing a list of target hosts (one
STDOUT                                    per line, format HOST[:PORT]).  Use --threads
STDOUT                                    to control concurrent scans.
STDOUT         --threads=<threads>    number of threads to use when scanning multiple
STDOUT                                    targets (-T/--targets) (default: 32)
STDOUT    -v,  --verbose          verbose output
STDOUT 
END 

STDOUT Starting audit of host.testcontainers.internal:2222...
STDOUT Connecting to 172.17.0.3:2222...
STDOUT Getting banner...
STDOUT KEX initialisation...
STDOUT (gen) banner: SSH-2.0-APACHE-SSHD-2.8.0
STDOUT [exception] did not receive MSG_KEXINIT (20), instead received unknown message (1)
END 
...

STDOUT Starting audit of host.testcontainers.internal:2222...
STDOUT Connecting to 172.17.0.3:2222...
STDOUT Getting banner...
STDOUT KEX initialisation...
STDOUT Preparing to perform DH group exchange using diffie-hellman-group-exchange-sha256...
STDOUT Connecting to 172.17.0.3:2222...
STDOUT Getting banner...
STDOUT KEX initialisation...
STDOUT Preparing to perform DH group exchange using diffie-hellman-group-exchange-sha256 with modulus size 512...
STDOUT Connecting to 172.17.0.3:2222...
STDOUT Getting banner...
STDOUT KEX initialisation...
STDOUT Preparing to perform DH group exchange using diffie-hellman-group-exchange-sha256 with modulus size 768...
STDOUT Connecting to 172.17.0.3:2222...
STDOUT Getting banner...
STDOUT KEX initialisation...
STDOUT Preparing to perform DH group exchange using diffie-hellman-group-exchange-sha256 with modulus size 1024...
STDOUT Connecting to 172.17.0.3:2222...
STDOUT Getting banner...
STDOUT KEX initialisation...
STDOUT Preparing to perform DH group exchange using diffie-hellman-group-exchange-sha256 with modulus size 1536...
STDOUT Connecting to 172.17.0.3:2222...
STDOUT Getting banner...
STDOUT KEX initialisation...
STDOUT Preparing to perform DH group exchange using diffie-hellman-group-exchange-sha256 with modulus size 2048...
STDOUT Connecting to 172.17.0.3:2222...
STDOUT Getting banner...
STDOUT KEX initialisation...
STDOUT (gen) banner: SSH-2.0-APACHE-SSHD-2.8.0
STDOUT (gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2018.76+
STDOUT (gen) compression: enabled (zlib, [email protected])
STDOUT (kex) curve25519-sha256 -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
STDOUT (kex) [email protected] -- [info] available since OpenSSH 6.5, Dropbear SSH 2013.62
STDOUT (kex) curve448-sha512
STDOUT (kex) diffie-hellman-group-exchange-sha256 (2048-bit) -- [info] available since OpenSSH 4.4
STDOUT (kex) diffie-hellman-group18-sha512 -- [info] available since OpenSSH 7.3
STDOUT (kex) diffie-hellman-group17-sha512
STDOUT (kex) diffie-hellman-group16-sha512 -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
STDOUT (kex) diffie-hellman-group15-sha512
STDOUT (kex) diffie-hellman-group14-sha256 -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
STDOUT (kex) ext-info-s
STDOUT (key) ecdsa-sha2-nistp521 -- [fail] using weak elliptic curves
STDOUT (key) ecdsa-sha2-nistp521 -- [warn] using weak random number generator could reveal the key
STDOUT (key) ecdsa-sha2-nistp521 -- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
STDOUT (enc) [email protected] -- [info] available since OpenSSH 6.5
STDOUT (enc) [email protected] -- [info] default cipher since OpenSSH 6.9.
STDOUT (enc) aes128-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
STDOUT (enc) aes192-ctr -- [info] available since OpenSSH 3.7
STDOUT (enc) aes256-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
STDOUT (enc) [email protected] -- [info] available since OpenSSH 6.2
STDOUT (enc) [email protected] -- [info] available since OpenSSH 6.2
STDOUT (mac) [email protected] -- [info] available since OpenSSH 6.2
STDOUT (mac) [email protected] -- [info] available since OpenSSH 6.2
STDOUT (rec) -ecdsa-sha2-nistp521-- key algorithm to remove 
STDOUT (nfo) For hardening guides on common OSes, please see: <https://www.ssh-audit.com/hardening_guides.html>
END