A verificação da chave do host falhou com o SSH

Question

Estou tentando conectar ao meu computador via OpenSSH no Ubuntu (remotamente ou da mesma máquina, terminal diferente), mas nenhum funciona. Quando tento me conectar remotamente com ssh username@ip_address , o terminal fica esperando, mas nada acontece. Quando tento me conectar da mesma máquina com ssh -v localhost , recebo a seguinte saída e erro:

OpenSSH_7.2p2 Ubuntu-4ubuntu2.1, OpenSSL 1.0.2g  1 Mar 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to localhost [127.0.0.1] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.1
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 pat OpenSSH* compat 0x04000000
debug1: Authenticating to localhost:22 as 'me'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: [email protected]
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:ybhcdw75C5wG/KnILBWaRnIA+NH8kGBFbi8yUIbUhl0
The authenticity of host 'localhost (127.0.0.1)' can't be established.
ECDSA key fingerprint is SHA256:ybhcdw75C5wG/KnILBWaRnIA+NH8kGBFbi8yUIbUhl0.
Are you sure you want to continue connecting (yes/no)? 
Host key verification failed.

Como posso resolver este problema? Eu tentei desativar a autenticação de senha, para obter a configuração menos segura, mas utilizável, mas ainda sem sorte.

Atualização:

Eu geramos chaves e agora recebo um erro diferente com ssh -v localhost , da seguinte maneira:

OpenSSH_7.2p2 Ubuntu-4ubuntu2.1, OpenSSL 1.0.2g  1 Mar 2016
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to localhost [127.0.0.1] port 22.
debug1: Connection established.
debug1: identity file /home/me/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.1
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 pat OpenSSH* compat 0x04000000
debug1: Authenticating to localhost:22 as 'me'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: [email protected]
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:ybhcdw75C5wG/KnILBWaRnIA+NH8kGBFbi8yUIbUhl0
debug1: Host 'localhost' is known and matches the ECDSA host key.
debug1: Found key in /home/me/.ssh/known_hosts:1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/me/.ssh/id_rsa
debug1: Authentications that can continue: publickey
debug1: Trying private key: /home/me/.ssh/id_dsa
debug1: Trying private key: /home/me/.ssh/id_ecdsa
debug1: Trying private key: /home/me/.ssh/id_ed25519
debug1: No more authentication methods to try.
Permission denied (publickey).

Qualquer ajuda seria apreciada. Obrigado,

    

Answer 1

primeira coisa:

Você gerou as próprias chaves ssh?

debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/me/.ssh/id_ed25519-cert type -1

isto diz que nenhuma chave pública e secreta foi encontrada ..

Além disso, quase todas as distribuições agora habilitaram StrictHostChecking = yes em / etc / ssh / ssh_config + permitiram apenas o protocolo ssh2 (btw. ssh1 permitindo ssh1 ser perigoso e totalmente inseguro )

Por fim, você permitiu login interativo ou apenas autenticação de chave pública?

    

Answer 2

Antes da sua atualização, você precisava inserir "yes" para aceitar a chave do host, de preferência depois de VERIFICAR POR MEIOS SECUNDÁRIOS se a chave do host remoto corresponde à impressão digital da chave exibida.

Após a atualização, você tinha uma chave em cache correspondente à chave do host anterior (antes de você gerá-la novamente) no arquivo ~/.ssh/known_hosts do cliente e precisa atualizar ou remover a linha correspondente nesse arquivo. Este é outro mecanismo que previne ataques man-in-the-middle onde alguém finge ser o host remoto, mas é claro que não pode falsificar a chave do host.