ssh-audit is a tool for ssh server & client configuration auditing.
jtesta/ssh-audit (v2.0+) is the updated and maintained version of ssh-audit forked from arthepsy/ssh-audit (v1.x) due to inactivity.
- 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;
- supports Python 3.7 - 3.11;
- no dependencies
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)
-d, --debug Enable debug output.
-g, --gex-test=<x[,y,...]> dh gex modulus size test
<min1:pref1:max1[,min2:pref2:max2,...]>
<x-y[:step]>
-j, --json JSON output (use -jj to enable indents)
-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, --manual print the man page (Windows only)
-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 name" | 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])
--threads=<threads> number of threads to use when scanning multiple
targets (-T/--targets) (default: 32)
-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 -p 2222 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 policy names with -P
/--policy
):
ssh-audit -L
To run a policy audit against a server:
ssh-audit -P ["policy name" | path/to/server_policy.txt] targetserver
To run a policy audit against a client:
ssh-audit -c -P ["policy name" | path/to/client_policy.txt]
To run a policy audit against many servers:
ssh-audit -T servers.txt -P ["policy name" | path/to/server_policy.txt]
To create a policy based on a target server (which can be manually edited):
ssh-audit -M new_policy.txt targetserver
Below is a screen shot of the standard server-auditing output when connecting to an unhardened OpenSSH v5.3 service:
Below is a screen shot of the policy auditing output when connecting to an un-hardened Ubuntu Server 20.04 machine (hint: use -L
/--list-policies
to see names of built-in policies to use with -P
/--policy
):
After applying the steps in the hardening guide (see below), the output changes to the following:
Below is a screen shot of the client-auditing output when an unhardened OpenSSH v7.2 client connects:
Guides to harden server & client configuration can be found here: https://www.ssh-audit.com/hardening_guides.html
Pre-built packages are available for Windows (see the releases page), PyPI, Snap, and Docker:
To install from PyPI:
$ pip3 install ssh-audit
To install the Snap package:
$ snap install ssh-audit
To install from Dockerhub:
$ docker pull positronsecurity/ssh-audit
(Then run with: docker run -it -p 2222:2222 positronsecurity/ssh-audit 10.1.1.1
)
The status of various other platform packages can be found below (via Repology):
For convenience, a web front-end on top of the command-line tool is available at https://www.ssh-audit.com/.
- Results from concurrent scans against multiple hosts are no longer improperly combined; bug discovered by Adam Russell.
- Hostname resolution failure no longer causes scans against multiple hosts to terminate unexpectedly; credit Dani Cuesta.
- Algorithm recommendations resulting from warnings are now printed in yellow instead of red; credit Adam Russell.
- Added failure, warning, and info notes to JSON output (note that this results in a breaking change to the banner protocol, "enc", and "mac" fields); credit Bareq Al-Azzawi.
- Docker Makefile now creates multi-arch builds for amd64, arm64, and armv7; credit Sebastian Cohnen.
- Fixed crash during GEX tests.
- Refined GEX testing against OpenSSH servers: when the fallback mechanism is suspected of being triggered, perform an additional test to obtain more accurate results.
- The color of all notes will be printed in green when the related algorithm is rated good.
- Prioritized host key certificate algorithms for Ubuntu 22.04 LTS client policy.
- Marked all NIST K-, B-, and T-curves as unproven since they are so rarely used.
- Added built-in policy for OpenSSH 9.4.
- Added 12 new host keys:
ecdsa-sha2-curve25519
,ecdsa-sha2-nistb233
,ecdsa-sha2-nistb409
,ecdsa-sha2-nistk163
,ecdsa-sha2-nistk233
,ecdsa-sha2-nistk283
,ecdsa-sha2-nistk409
,ecdsa-sha2-nistp224
,ecdsa-sha2-nistp192
,ecdsa-sha2-nistt571
,ssh-dsa
,x509v3-sign-rsa-sha256
. - Added 15 new key exchanges:
curve448-sha512@libssh.org
,ecdh-nistp256-kyber-512r3-sha256-d00@openquantumsafe.org
,ecdh-nistp384-kyber-768r3-sha384-d00@openquantumsafe.org
,ecdh-nistp521-kyber-1024r3-sha512-d00@openquantumsafe.org
,ecdh-sha2-brainpoolp256r1@genua.de
,ecdh-sha2-brainpoolp384r1@genua.de
,ecdh-sha2-brainpoolp521r1@genua.de
,kexAlgoDH14SHA1
,kexAlgoDH1SHA1
,kexAlgoECDH256
,kexAlgoECDH384
,kexAlgoECDH521
,sm2kep-sha2-nistp256
,x25519-kyber-512r3-sha256-d00@amazon.com
,x25519-kyber512-sha512@aws.amazon.com
. - Added 8 new ciphers:
aes192-gcm@openssh.com
,cast128-12-cbc
,cast128-12-cfb
,cast128-12-ecb
,cast128-12-ofb
,des-cfb
,des-ecb
,des-ofb
. - Added 14 new MACs:
cbcmac-3des
,cbcmac-aes
,cbcmac-blowfish
,cbcmac-des
,cbcmac-rijndael
,cbcmac-twofish
,hmac-sha256-96
,md5
,md5-8
,ripemd160
,ripemd160-8
,sha1
,sha1-8
,umac-128
.
- Dropped support for Python 3.6, as it reached EOL at the end of 2021.
- Added Ubuntu Server & Client 22.04 hardening policies.
- Removed experimental warning tag from
sntrup761x25519-sha512@openssh.com
. - Updated CVE database; credit Alexandre Zanni.
- Added
-g
and--gex-test
for granular GEX modulus size tests; credit Adam Russell. - Snap packages now print more user-friendly error messages when permission errors are encountered.
- JSON 'target' field now always includes port number; credit tomatohater1337.
- JSON output now includes recommendations and CVE data.
- Mixed host key/CA key types (i.e.: RSA host keys signed with ED25519 CAs, etc.) are now properly handled.
- Warnings are now printed for 2048-bit moduli; partial credit Adam Russell.
- SHA-1 algorithms now cause failures.
- CBC mode ciphers are now warnings instead of failures.
- Generic failure/warning messages replaced with more specific reasons (i.e.: 'using weak cipher' => 'using broken RC4 cipher').
- Updated built-in policies to include missing host key size information.
- Added built-in policies for OpenSSH 8.8, 8.9, 9.0, 9.1, 9.2, and 9.3.
- Added 33 new host keys:
dsa2048-sha224@libassh.org
,dsa2048-sha256@libassh.org
,dsa3072-sha256@libassh.org
,ecdsa-sha2-1.3.132.0.10-cert-v01@openssh.com
,eddsa-e382-shake256@libassh.org
,eddsa-e521-shake256@libassh.org
,null
,pgp-sign-dss
,pgp-sign-rsa
,spki-sign-dss
,spki-sign-rsa
,ssh-dss-sha224@ssh.com
,ssh-dss-sha384@ssh.com
,ssh-dss-sha512@ssh.com
,ssh-ed448-cert-v01@openssh.com
,ssh-rsa-sha224@ssh.com
,ssh-rsa-sha2-256
,ssh-rsa-sha2-512
,ssh-rsa-sha384@ssh.com
,ssh-rsa-sha512@ssh.com
,ssh-xmss-cert-v01@openssh.com
,ssh-xmss@openssh.com
,webauthn-sk-ecdsa-sha2-nistp256@openssh.com
,x509v3-ecdsa-sha2-1.3.132.0.10
,x509v3-sign-dss-sha1
,x509v3-sign-dss-sha224@ssh.com
,x509v3-sign-dss-sha256@ssh.com
,x509v3-sign-dss-sha384@ssh.com
,x509v3-sign-dss-sha512@ssh.com
,x509v3-sign-rsa-sha1
,x509v3-sign-rsa-sha224@ssh.com
,x509v3-sign-rsa-sha384@ssh.com
,x509v3-sign-rsa-sha512@ssh.com
. - Added 46 new key exchanges:
diffie-hellman-group14-sha224@ssh.com
,diffie-hellman_group17-sha512
,diffie-hellman-group-exchange-sha224@ssh.com
,diffie-hellman-group-exchange-sha384@ssh.com
,ecdh-sha2-1.2.840.10045.3.1.1
,ecdh-sha2-1.2.840.10045.3.1.7
,ecdh-sha2-1.3.132.0.1
,ecdh-sha2-1.3.132.0.16
,ecdh-sha2-1.3.132.0.26
,ecdh-sha2-1.3.132.0.27
,ecdh-sha2-1.3.132.0.33
,ecdh-sha2-1.3.132.0.34
,ecdh-sha2-1.3.132.0.35
,ecdh-sha2-1.3.132.0.36
,ecdh-sha2-1.3.132.0.37
,ecdh-sha2-1.3.132.0.38
,ecdh-sha2-4MHB+NBt3AlaSRQ7MnB4cg==
,ecdh-sha2-5pPrSUQtIaTjUSt5VZNBjg==
,ecdh-sha2-9UzNcgwTlEnSCECZa7V1mw==
,ecdh-sha2-D3FefCjYoJ/kfXgAyLddYA==
,ecdh-sha2-h/SsxnLCtRBh7I9ATyeB3A==
,ecdh-sha2-m/FtSAmrV4j/Wy6RVUaK7A==
,ecdh-sha2-mNVwCXAoS1HGmHpLvBC94w==
,ecdh-sha2-qCbG5Cn/jjsZ7nBeR7EnOA==
,ecdh-sha2-qcFQaMAMGhTziMT0z+Tuzw==
,ecdh-sha2-VqBg4QRPjxx1EXZdV0GdWQ==
,ecdh-sha2-wiRIU8TKjMZ418sMqlqtvQ==
,ecdh-sha2-zD/b3hu/71952ArpUG4OjQ==
,ecmqv-sha2
,gss-13.3.132.0.10-sha256-*
,gss-curve25519-sha256-*
,gss-curve448-sha512-*
,gss-gex-sha1-*
,gss-gex-sha256-*
,gss-group14-sha1-*
,gss-group14-sha256-*
,gss-group15-sha512-*
,gss-group16-sha512-*
,gss-group17-sha512-*
,gss-group18-sha512-*
,gss-group1-sha1-*
,gss-nistp256-sha256-*
,gss-nistp384-sha256-*
,gss-nistp521-sha512-*
,m383-sha384@libassh.org
,m511-sha512@libassh.org
. - Added 28 new ciphers:
3des-cfb
,3des-ecb
,3des-ofb
,blowfish-cfb
,blowfish-ecb
,blowfish-ofb
,camellia128-cbc@openssh.org
,camellia128-ctr@openssh.org
,camellia192-cbc@openssh.org
,camellia192-ctr@openssh.org
,camellia256-cbc@openssh.org
,camellia256-ctr@openssh.org
,cast128-cfb
,cast128-ecb
,cast128-ofb
,cast128-12-cbc@ssh.com
,idea-cfb
,idea-ecb
,idea-ofb
,rijndael-cbc@ssh.com
,seed-ctr@ssh.com
,serpent128-gcm@libassh.org
,serpent256-gcm@libassh.org
,twofish128-gcm@libassh.org
,twofish256-gcm@libassh.org
,twofish-cfb
,twofish-ecb
,twofish-ofb
- Added 5 new MACs:
hmac-sha1-96@openssh.com
,hmac-sha224@ssh.com
,hmac-sha256-2@ssh.com
,hmac-sha384@ssh.com
,hmac-whirlpool
.
- Fixed crash when running host key tests.
- Handles server connection failures more gracefully.
- Now prints JSON with indents when
-jj
is used (useful for debugging). - Added MD5 fingerprints to verbose output.
- Added
-d
/--debug
option for getting debugging output; credit Adam Russell. - Updated JSON output to include MD5 fingerprints. Note that this results in a breaking change in the 'fingerprints' dictionary format.
- Updated OpenSSH 8.1 (and earlier) policies to include
rsa-sha2-512
andrsa-sha2-256
. - Added OpenSSH v8.6 & v8.7 policies.
- Added 3 new key exchanges:
gss-gex-sha1-eipGX3TCiQSrx573bT1o1Q==
,gss-group1-sha1-eipGX3TCiQSrx573bT1o1Q==
, andgss-group14-sha1-eipGX3TCiQSrx573bT1o1Q==
. - Added 3 new MACs:
hmac-ripemd160-96
,AEAD_AES_128_GCM
, andAEAD_AES_256_GCM
.
- Added multi-threaded scanning support.
- Added built-in Windows manual page (see
-m
/--manual
); credit Adam Russell. - Added version check for OpenSSH user enumeration (CVE-2018-15473).
- Added deprecation note to host key types based on SHA-1.
- Added extra warnings for SSHv1.
- Added built-in hardened OpenSSH v8.5 policy.
- Upgraded warnings to failures for host key types based on SHA-1.
- Fixed crash when receiving unexpected response during host key test.
- Fixed hang against older Cisco devices during host key test & gex test.
- Fixed improper termination while scanning multiple targets when one target returns an error.
- Dropped support for Python 3.5 (which reached EOL in Sept. 2020).
- Added 1 new key exchange:
sntrup761x25519-sha512@openssh.com
.
- Now parses public key sizes for
rsa-sha2-256-cert-v01@openssh.com
andrsa-sha2-512-cert-v01@openssh.com
host key types. - Flag
ssh-rsa-cert-v01@openssh.com
as a failure due to SHA-1 hash. - Fixed bug in recommendation output which suppressed some algorithms inappropriately.
- Built-in policies now include CA key requirements (if certificates are in use).
- Lookup function (
--lookup
) now performs case-insensitive lookups of similar algorithms; credit Adam Russell. - Migrated pre-made policies from external files to internal database.
- Split single 3,500 line script into many files (by class).
- Added setup.py support; credit Ganden Schaffner.
- Added 1 new cipher:
des-cbc@ssh.com
.
- 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.
- Added feature to look up algorithms in internal database (see
--lookup
); credit Adam Russell. - 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
.
- Marked host key type
ssh-rsa
as weak due to practical SHA-1 collisions. - 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
, andsk-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-
, andgss-group1-sha1-
. - Added 9 new ciphers:
camellia128-cbc
,camellia128-ctr
,camellia192-cbc
,camellia192-ctr
,camellia256-cbc
,camellia256-ctr
,aes128-gcm
,aes256-gcm
, andchacha20-poly1305
. - Added 2 new MACs:
aes128-gcm
andaes256-gcm
.
- 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.
- Added client software auditing functionality (see
-c
/--client-audit
option). - Added JSON output option (see
-j
/--json
option; credit Andreas Jaggi). - 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
.
- 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.
- 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
- 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)
- 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)
- implement batch output option
- implement minimum output level option
- fix compatibility with Python 2.6
- implement SSH version compatibility feature
- fix wrong mac algorithm warning
- fix Dropbear SSH version typo
- parse pre-banner header
- better errors handling
- use OpenSSH 7.3 banner
- add new key-exchange algorithms
- 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
- multiple additional warnings
- support for none algorithm
- better compression handling
- ensure reading enough data (fixes few Linux SSH)
- Dropbear SSH support
- initial version