# general (gen) banner: SSH-2.0-OpenSSH_8.0 (gen) software: OpenSSH 8.0 (gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2020.79+ (gen) compression: enabled (zlib@openssh.com) # key exchange algorithms (kex) curve25519-sha256 -- [warn] does not provide protection against post-quantum attacks `- [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 -- [warn] does not provide protection against post-quantum attacks `- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62 `- [info] default key exchange from OpenSSH 6.5 to 7.3 (kex) diffie-hellman-group-exchange-sha256 (4096-bit) -- [warn] does not provide protection against post-quantum attacks `- [info] available since OpenSSH 4.4 `- [info] OpenSSH's GEX fallback mechanism was triggered during testing. Very old SSH clients will still be able to create connections using a 2048-bit modulus, though modern clients will use 4096. This can only be disabled by recompiling the code (see https://github.com/openssh/openssh-portable/blob/V_9_4/dh.c#L477). # host-key algorithms (key) ssh-ed25519 -- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79 # encryption algorithms (ciphers) (enc) chacha20-poly1305@openssh.com -- [warn] vulnerable to the Terrapin attack (CVE-2023-48795), allowing message prefix truncation `- [info] available since OpenSSH 6.5, Dropbear SSH 2020.79 `- [info] default cipher since OpenSSH 6.9 (enc) aes256-gcm@openssh.com -- [info] available since OpenSSH 6.2 (enc) aes128-gcm@openssh.com -- [info] available since OpenSSH 6.2 (enc) aes256-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52 (enc) aes192-ctr -- [info] available since OpenSSH 3.7 (enc) aes128-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52 # message authentication code algorithms (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) umac-128-etm@openssh.com -- [info] available since OpenSSH 6.2 # fingerprints (fin) ssh-ed25519: SHA256:UrnXIVH+7dlw8UqYocl48yUEcKrthGDQG2CPCgp7MxU # algorithm recommendations (for OpenSSH 8.0) (rec) +rsa-sha2-256 -- key algorithm to append  (rec) +rsa-sha2-512 -- key algorithm to append  (rec) !diffie-hellman-group-exchange-sha256 -- kex algorithm to change (increase modulus size to 3072 bits or larger)  (rec) -chacha20-poly1305@openssh.com -- enc algorithm to remove  (rec) -curve25519-sha256 -- kex algorithm to remove  (rec) -curve25519-sha256@libssh.org -- kex algorithm to remove  # additional info (nfo) For hardening guides on common OSes, please see: