Pentesting SSH - Port 22

A list of Pentesting Techniques for SSH service.

ssh_audit

ssh-audit is a tool used to audit configuration of SSH client and server.

Installation

pip3 install ssh-audit
snap install ssh-audit
docker pull positronsecurity/ssh-audit

Launching

ssh-audit <IP_ADDRESS>
# Using docker
docker run -it -p <HOST_PORT>:2222 positronsecurity/ssh-audit <IP_ADDRESS>

Example

└─$ ssh-audit -p 2222 172.17.0.2
# general
(gen) banner: SSH-2.0-OpenSSH_8.1
(gen) software: OpenSSH 8.1
(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2018.76+
(gen) compression: enabled ([e-mail])

# key exchange algorithms
(kex) curve25519-sha256                     -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
(kex) [e-mail]          -- [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 (2048-bit) -- [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-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

# host-key algorithms
(key) rsa-sha2-512 (3072-bit)               -- [info] available since OpenSSH 7.2
(key) rsa-sha2-256 (3072-bit)               -- [info] available since OpenSSH 7.2
(key) ssh-rsa (3072-bit)                    -- [fail] using weak hashing algorithm
                                            `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
                                            `- [info] a future deprecation notice has been issued in OpenSSH 8.2: https://www.openssh.com/txt/release-8.2
(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) ssh-ed25519                           -- [info] available since OpenSSH 6.5

# encryption algorithms (ciphers)
(enc) [e-mail]         -- [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) [e-mail]                -- [info] available since OpenSSH 6.2
(enc) [e-mail]                -- [info] available since OpenSSH 6.2

# message authentication code algorithms
(mac) [e-mail]               -- [warn] using small 64-bit tag size
                                            `- [info] available since OpenSSH 6.2
(mac) [e-mail]              -- [info] available since OpenSSH 6.2
(mac) [e-mail]         -- [info] available since OpenSSH 6.2
(mac) [e-mail]         -- [info] available since OpenSSH 6.2
(mac) [e-mail]             -- [warn] using weak hashing algorithm
                                            `- [info] available since OpenSSH 6.2
(mac) [e-mail]                   -- [warn] using encrypt-and-MAC mode
                                            `- [warn] using small 64-bit tag size
                                            `- [info] available since OpenSSH 4.7
(mac) [e-mail]                  -- [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

# fingerprints
(fin) ssh-ed25519: SHA256:CQeBJuUUku/s4AFN2MgSpC/7C0zPdUsXpMDArBjh+cc
(fin) ssh-rsa: SHA256:JXBCNPntbRCUAdrSL3+am2oPHqufoB+0wd5xqvgNWlk

# algorithm recommendations (for OpenSSH 8.1)
(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) -ssh-rsa                              -- key algorithm to remove 
(rec) -diffie-hellman-group14-sha1          -- kex algorithm to remove 
(rec) -hmac-sha1                            -- mac algorithm to remove 
(rec) [e-mail]            -- mac algorithm to remove 
(rec) -hmac-sha2-256                        -- mac algorithm to remove 
(rec) -hmac-sha2-512                        -- mac algorithm to remove 
(rec) [e-mail]                 -- mac algorithm to remove 
(rec) [e-mail]              -- mac algorithm to remove 
(rec) [e-mail]                  -- mac algorithm to remove 

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

Github: https://github.com/jtesta/ssh-audit