ssh-audit/README.md
2020-10-11 14:44:28 -04:00

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# ssh-audit
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**ssh-audit** is a tool for ssh server & client configuration auditing.
[jtesta/ssh-audit](https://github.com/jtesta/ssh-audit/) (v2.0+) is the updated and maintained version of ssh-audit forked from [arthepsy/ssh-audit](https://github.com/arthepsy/ssh-audit) (v1.x) due to inactivity.
## Features
- SSH1 and SSH2 protocol server support;
- 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 information (available since, removed/disabled, unsafe/weak/legacy, etc);
- output algorithm recommendations (append or remove based on recognized software version);
- output security information (related issues, assigned CVE list, etc);
- analyze SSH version compatibility based on algorithm information;
- historical information from OpenSSH, Dropbear SSH and libssh;
- policy scans to ensure adherence to a hardened/standard configuration;
- runs on Linux and Windows;
- no dependencies
## Usage
```
usage: ssh-audit.py [options] <host>
-h, --help print this help
-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
-c, --client-audit starts a server on port 2222 to audit client
software config (use -p to change port;
use -t to change timeout)
-j, --json JSON output
-l, --level=<level> minimum output level (info|warn|fail)
-L, --list-policies list all the official, built-in policies
--lookup=<alg1,alg2,...> looks up an algorithm(s) without
connecting to a server
-M, --make-policy=<policy.txt> creates a policy based on the target server
(i.e.: the target server has the ideal
configuration that other servers should
adhere to)
-n, --no-colors disable colors
-p, --port=<port> port to connect
-P, --policy=<policy.txt> run a policy test using the specified policy
-t, --timeout=<secs> timeout (in seconds) for connection and reading
(default: 5)
-T, --targets=<hosts.txt> a file containing a list of target hosts (one
per line, format HOST[:PORT])
-v, --verbose verbose output
```
* if both IPv4 and IPv6 are used, order of precedence can be set by using either `-46` or `-64`.
* batch flag `-b` will output sections without header and without empty lines (implies verbose flag).
* verbose flag `-v` will prefix each line with section type and algorithm name.
* an exit code of 0 is returned when all algorithms are considered secure (for a standard audit), or when a policy check passes (for a policy audit).
Basic server auditing:
```
ssh-audit localhost
ssh-audit 127.0.0.1
ssh-audit 127.0.0.1:222
ssh-audit ::1
ssh-audit [::1]:222
```
To run a standard audit against many servers (place targets into servers.txt, one on each line in the format of `HOST[:PORT]`):
```
ssh-audit -T servers.txt
```
To audit a client configuration (listens on port 2222 by default; connect using `ssh anything@localhost`):
```
ssh-audit -c
```
To audit a client configuration, with a listener on port 4567:
```
ssh-audit -c -p 4567
```
To list all official built-in policies (hint: use resulting file paths with `-P`/`--policy`):
```
ssh-audit -L
```
To run a policy audit against a server:
```
ssh-audit -P path/to/server_policy targetserver
```
To run a policy audit against a client:
```
ssh-audit -c -P path/to/client_policy
```
To run a policy audit against many servers:
```
ssh-audit -T servers.txt -P path/to/server_policy
```
To create a policy based on a target server (which can be manually edited; see official built-in policies for syntax examples):
```
ssh-audit -M new_policy.txt targetserver
```
### Server Standard Audit Example
Below is a screen shot of the standard server-auditing output when connecting to an unhardened OpenSSH v5.3 service:
![screenshot](https://user-images.githubusercontent.com/2982011/64388792-317e6f80-d00e-11e9-826e-a4934769bb07.png)
### Server Policy Audit Example
Below is a screen shot of the policy auditing output when connecting to an un-hardened Ubuntu Server 20.04 machine:
![screenshot](https://user-images.githubusercontent.com/2982011/94370881-95178700-00c0-11eb-8705-3157a4669dc0.png)
After applying the steps in the hardening guide (see below), the output changes to the following:
![screenshot](https://user-images.githubusercontent.com/2982011/94370873-87620180-00c0-11eb-9a59-469f61a56ce1.png)
### Client Standard Audit Example
Below is a screen shot of the client-auditing output when an unhardened OpenSSH v7.2 client connects:
![client_screenshot](https://user-images.githubusercontent.com/2982011/68867998-b946c100-06c4-11ea-975f-1f47e4178a74.png)
### Hardening Guides
Guides to harden server & client configuration can be found here: [https://www.ssh-audit.com/hardening_guides.html](https://www.ssh-audit.com/hardening_guides.html)
### Pre-Built Packages
Pre-built packages are available for Windows (see the releases page), on PyPI, Snap, and Homebrew.
To install from PyPI:
```
$ pip3 install ssh-audit
```
To install the Snap package:
```
$ snap install ssh-audit
```
To install on Homebrew:
```
$ brew install ssh-audit
```
### Web Front-End
For convenience, a web front-end on top of the command-line tool is available at [https://www.ssh-audit.com/](https://www.ssh-audit.com/).
## ChangeLog
### v2.3.1-dev (???)
- Added setup.py support; credit [Ganden Schaffner](https://github.com/gschaffner)
- Added 1 new cipher: `des-cbc@ssh.com`.
### v2.3.0 (2020-09-27)
- Added new policy auditing functionality to test adherence to a hardening guide/standard configuration (see `-L`/`--list-policies`, `-M`/`--make-policy` and `-P`/`--policy`). For an in-depth tutorial, see <https://www.positronsecurity.com/blog/2020-09-27-ssh-policy-configuration-checks-with-ssh-audit/>.
- Created new man page (see `ssh-audit.1` file).
- 1024-bit moduli upgraded from warnings to failures.
- Many Python 2 code clean-ups, testing framework improvements, pylint & flake8 fixes, and mypy type comments; credit [Jürgen Gmach](https://github.com/jugmac00).
- Added feature to look up algorithms in internal database (see `--lookup`); credit [Adam Russell](https://github.com/thecliguy).
- Suppress recommendation of token host key types.
- Added check for use-after-free vulnerability in PuTTY v0.73.
- Added 11 new host key types: `ssh-rsa1`, `ssh-dss-sha256@ssh.com`, `ssh-gost2001`, `ssh-gost2012-256`, `ssh-gost2012-512`, `spki-sign-rsa`, `ssh-ed448`, `x509v3-ecdsa-sha2-nistp256`, `x509v3-ecdsa-sha2-nistp384`, `x509v3-ecdsa-sha2-nistp521`, `x509v3-rsa2048-sha256`.
- Added 8 new key exchanges: `diffie-hellman-group1-sha256`, `kexAlgoCurve25519SHA256`, `Curve25519SHA256`, `gss-group14-sha256-`, `gss-group15-sha512-`, `gss-group16-sha512-`, `gss-nistp256-sha256-`, `gss-curve25519-sha256-`.
- Added 5 new ciphers: `blowfish`, `AEAD_AES_128_GCM`, `AEAD_AES_256_GCM`, `crypticore128@ssh.com`, `seed-cbc@ssh.com`.
- Added 3 new MACs: `chacha20-poly1305@openssh.com`, `hmac-sha3-224`, `crypticore-mac@ssh.com`.
### v2.2.0 (2020-03-11)
- Marked host key type `ssh-rsa` as weak due to [practical SHA-1 collisions](https://eprint.iacr.org/2020/014.pdf).
- Added Windows builds.
- Added 10 new host key types: `ecdsa-sha2-1.3.132.0.10`, `x509v3-sign-dss`, `x509v3-sign-rsa`, `x509v3-sign-rsa-sha256@ssh.com`, `x509v3-ssh-dss`, `x509v3-ssh-rsa`, `sk-ecdsa-sha2-nistp256-cert-v01@openssh.com`, `sk-ecdsa-sha2-nistp256@openssh.com`, `sk-ssh-ed25519-cert-v01@openssh.com`, and `sk-ssh-ed25519@openssh.com`.
- Added 18 new key exchanges: `diffie-hellman-group14-sha256@ssh.com`, `diffie-hellman-group15-sha256@ssh.com`, `diffie-hellman-group15-sha384@ssh.com`, `diffie-hellman-group16-sha384@ssh.com`, `diffie-hellman-group16-sha512@ssh.com`, `diffie-hellman-group18-sha512@ssh.com`, `ecdh-sha2-curve25519`, `ecdh-sha2-nistb233`, `ecdh-sha2-nistb409`, `ecdh-sha2-nistk163`, `ecdh-sha2-nistk233`, `ecdh-sha2-nistk283`, `ecdh-sha2-nistk409`, `ecdh-sha2-nistp192`, `ecdh-sha2-nistp224`, `ecdh-sha2-nistt571`, `gss-gex-sha1-`, and `gss-group1-sha1-`.
- Added 9 new ciphers: `camellia128-cbc`, `camellia128-ctr`, `camellia192-cbc`, `camellia192-ctr`, `camellia256-cbc`, `camellia256-ctr`, `aes128-gcm`, `aes256-gcm`, and `chacha20-poly1305`.
- Added 2 new MACs: `aes128-gcm` and `aes256-gcm`.
### v2.1.1 (2019-11-26)
- Added 2 new host key types: `rsa-sha2-256-cert-v01@openssh.com`, `rsa-sha2-512-cert-v01@openssh.com`.
- Added 2 new ciphers: `des`, `3des`.
- Added 3 new PuTTY vulnerabilities.
- During client testing, client IP address is now listed in output.
### v2.1.0 (2019-11-14)
- Added client software auditing functionality (see `-c` / `--client-audit` option).
- Added JSON output option (see `-j` / `--json` option; credit [Andreas Jaggi](https://github.com/x-way)).
- Fixed crash while scanning Solaris Sun_SSH.
- Added 9 new key exchanges: `gss-group1-sha1-toWM5Slw5Ew8Mqkay+al2g==`, `gss-gex-sha1-toWM5Slw5Ew8Mqkay+al2g==`, `gss-group14-sha1-`, `gss-group14-sha1-toWM5Slw5Ew8Mqkay+al2g==`, `gss-group14-sha256-toWM5Slw5Ew8Mqkay+al2g==`, `gss-group15-sha512-toWM5Slw5Ew8Mqkay+al2g==`, `diffie-hellman-group15-sha256`, `ecdh-sha2-1.3.132.0.10`, `curve448-sha512`.
- Added 1 new host key type: `ecdsa-sha2-1.3.132.0.10`.
- Added 4 new ciphers: `idea-cbc`, `serpent128-cbc`, `serpent192-cbc`, `serpent256-cbc`.
- Added 6 new MACs: `hmac-sha2-256-96-etm@openssh.com`, `hmac-sha2-512-96-etm@openssh.com`, `hmac-ripemd`, `hmac-sha256-96@ssh.com`, `umac-32@openssh.com`, `umac-96@openssh.com`.
### v2.0.0 (2019-08-29)
- Forked from https://github.com/arthepsy/ssh-audit (development was stalled, and developer went MIA).
- Added RSA host key length test.
- Added RSA certificate key length test.
- Added Diffie-Hellman modulus size test.
- Now outputs host key fingerprints for RSA and ED25519.
- Added 5 new key exchanges: `sntrup4591761x25519-sha512@tinyssh.org`, `diffie-hellman-group-exchange-sha256@ssh.com`, `diffie-hellman-group-exchange-sha512@ssh.com`, `diffie-hellman-group16-sha256`, `diffie-hellman-group17-sha512`.
- Added 3 new encryption algorithms: `des-cbc-ssh1`, `blowfish-ctr`, `twofish-ctr`.
- Added 10 new MACs: `hmac-sha2-56`, `hmac-sha2-224`, `hmac-sha2-384`, `hmac-sha3-256`, `hmac-sha3-384`, `hmac-sha3-512`, `hmac-sha256`, `hmac-sha256@ssh.com`, `hmac-sha512`, `hmac-512@ssh.com`.
- Added command line argument (`-t` / `--timeout`) for connection & reading timeouts.
- Updated CVEs for libssh & Dropbear.
### v1.7.0 (2016-10-26)
- implement options to allow specify IPv4/IPv6 usage and order of precedence
- implement option to specify remote port (old behavior kept for compatibility)
- add colors support for Microsoft Windows via optional colorama dependency
- fix encoding and decoding issues, add tests, do not crash on encoding errors
- use mypy-lang for static type checking and verify all code
### v1.6.0 (2016-10-14)
- implement algorithm recommendations section (based on recognized software)
- implement full libssh support (version history, algorithms, security, etc)
- fix SSH-1.99 banner recognition and version comparison functionality
- do not output empty algorithms (happens for misconfigured servers)
- make consistent output for Python 3.x versions
- add a lot more tests (conf, banner, software, SSH1/SSH2, output, etc)
- use Travis CI to test for multiple Python versions (2.6-3.5, pypy, pypy3)
### v1.5.0 (2016-09-20)
- create security section for related security information
- match and output assigned CVE list and security issues for Dropbear SSH
- implement full SSH1 support with fingerprint information
- automatically fallback to SSH1 on protocol mismatch
- add new options to force SSH1 or SSH2 (both allowed by default)
- parse banner information and convert it to specific software and OS version
- do not use padding in batch mode
- several fixes (Cisco sshd, rare hangs, error handling, etc)
### v1.0.20160902
- implement batch output option
- implement minimum output level option
- fix compatibility with Python 2.6
### v1.0.20160812
- implement SSH version compatibility feature
- fix wrong mac algorithm warning
- fix Dropbear SSH version typo
- parse pre-banner header
- better errors handling
### v1.0.20160803
- use OpenSSH 7.3 banner
- add new key-exchange algorithms
### v1.0.20160207
- use OpenSSH 7.2 banner
- additional warnings for OpenSSH 7.2
- fix OpenSSH 7.0 failure messages
- add rijndael-cbc failure message from OpenSSH 6.7
### v1.0.20160105
- multiple additional warnings
- support for none algorithm
- better compression handling
- ensure reading enough data (fixes few Linux SSH)
### v1.0.20151230
- Dropbear SSH support
### v1.0.20151223
- initial version