Ssh-audit

ssh-audit – Tool zur Überprüfung der Konfiguration von SSH-Servern und -Clients

Beschreibung

ssh-audit analysiert die Konfiguration von SSH-Servern und -Clients und warnt den Benutzer vor schwachen, veralteten und/oder ungetesteten kryptografischen Primitiven.

Es ist nützlich für die Absicherung von SSH-Tunneln, die standardmäßig eher auf Kompatibilität als auf Sicherheit ausgelegt sind.

Installation

apt install ssh-audit

Aufruf

Optionen

Unix	GNU	Parameter	Beschreibung

Exit-Status

Wert	Beschreibung
0	Erfolg
>0	Fehler

Anwendung

ssh-audit lab.foxtom.de -p2227

# general
(gen) banner: SSH-2.0-OpenSSH_10.0p2 Debian-7+deb13u4
(gen) software: OpenSSH 10.0p2
(gen) compatibility: OpenSSH 9.9+, Dropbear SSH 2020.79+
(gen) compression: enabled (zlib@openssh.com)

# key exchange algorithms
(kex) mlkem768x25519-sha256               -- [info] available since OpenSSH 9.9
                                          `- [info] hybrid key exchange based on post-quantum resistant algorithm and proven conventional X25519 algorithm
(kex) sntrup761x25519-sha512              -- [info] available since OpenSSH 9.9
                                          `- [info] default key exchange since OpenSSH 9.9
                                          `- [info] hybrid key exchange based on post-quantum resistant algorithm and proven conventional X25519 algorithm
(kex) sntrup761x25519-sha512@openssh.com  -- [info] available since OpenSSH 8.5
                                          `- [info] default key exchange from OpenSSH 9.0 to 9.8
                                          `- [info] hybrid key exchange based on post-quantum resistant algorithm and proven conventional X25519 algorithm
(kex) curve25519-sha256                   -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
                                          `- [info] default key exchange from OpenSSH 7.4 to 8.9
(kex) curve25519-sha256@libssh.org        -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
                                          `- [info] default key exchange from OpenSSH 6.5 to 7.3
(kex) ecdh-sha2-nistp256                  -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                          `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp384                  -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                          `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp521                  -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                          `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ext-info-s                          -- [info] available since OpenSSH 9.6
                                          `- [info] pseudo-algorithm that denotes the peer supports RFC8308 extensions
(kex) kex-strict-s-v00@openssh.com        -- [info] pseudo-algorithm that denotes the peer supports a stricter key exchange method as a counter-measure to the Terrapin attack (CVE-2023-48795)

# 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, Dropbear SSH 2020.79
(key) ecdsa-sha2-nistp256                 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                          `- [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, Dropbear SSH 2020.79

# encryption algorithms (ciphers)
(enc) chacha20-poly1305@openssh.com       -- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79
                                          `- [info] default cipher since OpenSSH 6.9
(enc) aes128-gcm@openssh.com              -- [info] available since OpenSSH 6.2
(enc) aes256-gcm@openssh.com              -- [info] available since OpenSSH 6.2
(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

# message authentication code algorithms
(mac) umac-64-etm@openssh.com             -- [warn] using small 64-bit tag size
                                          `- [info] available since OpenSSH 6.2
(mac) umac-128-etm@openssh.com            -- [info] available since OpenSSH 6.2
(mac) hmac-sha2-256-etm@openssh.com       -- [info] available since OpenSSH 6.2
(mac) hmac-sha2-512-etm@openssh.com       -- [info] available since OpenSSH 6.2
(mac) hmac-sha1-etm@openssh.com           -- [fail] using broken SHA-1 hash algorithm
                                          `- [info] available since OpenSSH 6.2
(mac) umac-64@openssh.com                 -- [warn] using encrypt-and-MAC mode
                                          `- [warn] using small 64-bit tag size
                                          `- [info] available since OpenSSH 4.7
(mac) umac-128@openssh.com                -- [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                           -- [fail] using broken SHA-1 hash algorithm
                                          `- [warn] using encrypt-and-MAC mode
                                          `- [info] available since OpenSSH 2.1.0, Dropbear SSH 0.28

# fingerprints
(fin) ssh-ed25519: SHA256:DFhaQQE8WTAeb+EgBRnpE8cIUwtOG5npSnDujuiuez8
(fin) ssh-rsa: SHA256:9cEQTa3rK/Y8gqBZTYBfgmpg5uz+8jslcAUDhwho6g0

# additional info
(nfo) Be aware that, while this target properly supports the strict key exchange method (via the kex-strict-?-v00@openssh.com marker) needed to protect against the Terrapin vulnerability (CVE-2023-48795), all peers must also support this feature as well, otherwise the vulnerability will still be present.  The following algorithms would allow an unpatched peer to create vulnerable SSH channels with this target: chacha20-poly1305@openssh.com.  If any CBC ciphers are in this list, you may remove them while leaving the *-etm@openssh.com MACs in place; these MACs are fine while paired with non-CBC cipher types.

Konfiguration

Dateien

Datei	Beschreibung

Anhang

---

Dokumentation

Man-Page

1. ssh-audit(1)