lowen.f
By:
lowen.f

suddenly SSH key doesn't work anymore and password is needed

April 24, 2017 1.5k views
Networking Security Ubuntu

As the topic says, suddenly I can't login anymore. I tried the following:

  • go back to a backup of 5 days ago
  • change permissions locally of my keys
  • deleted known hosts

This is the log when using -vvv

OpenSSH7.4p1, LibreSSL 2.5.0
debug1: Reading configuration data /etc/ssh/ssh
config
debug2: resolving "178.62.186.144" port 1526
debug2: sshconnectdirect: needpriv 0
debug1: Connecting to 178.62.186.144 [178.62.186.144] port 1526.
debug1: Connection established.
debug1: identity file /Users/flowen/.ssh/idrsa type 1
debug1: key
loadpublic: No such file or directory
debug1: identity file /Users/flowen/.ssh/id
rsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH7.4
debug1: Remote protocol version 2.0, remote software version OpenSSH
6.6.1p1 Ubuntu-2ubuntu2.8
debug1: match: OpenSSH6.6.1p1 Ubuntu-2ubuntu2.8 pat OpenSSH6.6.1* compat 0x04000000
debug2: fd 3 setting ONONBLOCK
debug1: Authenticating to 178.62.186.144:1526 as 'lowenf'
debug3: put
hostport: [178.62.186.144]:1526
debug3: hostkeys
foreach: reading file "/Users/flowen/.ssh/knownhosts"
debug3: record
hostkey: found key type RSA in file /Users/flowen/.ssh/knownhosts:16
debug3: record
hostkey: found key type ECDSA in file /Users/flowen/.ssh/knownhosts:27
debug3: load
hostkeys: loaded 2 keys from [178.62.186.144]:1526
debug3: orderhostkeyalgs: prefer hostkeyalgs: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug3: send packet: type 20
debug1: SSH2
MSGKEXINIT sent
debug3: receive packet: type 20
debug1: SSH2
MSGKEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-ed25519-cert-v01@openssh.com,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first
kexfollows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm@openssh.com,aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: MACs ctos: hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: MACs stoc: hmac-md5-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-ripemd160-etm@openssh.com,hmac-sha1-96-etm@openssh.com,hmac-md5-96-etm@openssh.com,hmac-md5,hmac-sha1,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos:
debug2: languages stoc:
debug2: first
kexfollows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2
MSGKEXECDHREPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:67niY4MSlwyf58cvFVU3nTP/7S9jYU/b+7/8IFPJNiI
debug3: put
hostport: [178.62.186.144]:1526
debug3: put
hostport: [178.62.186.144]:1526
debug3: hostkeys
foreach: reading file "/Users/flowen/.ssh/knownhosts"
debug3: record
hostkey: found key type RSA in file /Users/flowen/.ssh/knownhosts:16
debug3: record
hostkey: found key type ECDSA in file /Users/flowen/.ssh/knownhosts:27
debug3: load
hostkeys: loaded 2 keys from [178.62.186.144]:1526
debug3: hostkeysforeach: reading file "/Users/flowen/.ssh/knownhosts"
debug3: recordhostkey: found key type RSA in file /Users/flowen/.ssh/knownhosts:16
debug3: recordhostkey: found key type ECDSA in file /Users/flowen/.ssh/knownhosts:27
debug3: loadhostkeys: loaded 2 keys from [178.62.186.144]:1526
debug1: Host '[178.62.186.144]:1526' is known and matches the ECDSA host key.
debug1: Found key in /Users/flowen/.ssh/known
hosts:27
debug3: send packet: type 21
debug2: setnewkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2
MSGNEWKEYS sent
debug1: expecting SSH2
MSGNEWKEYS
debug3: receive packet: type 21
debug1: SSH2
MSGNEWKEYS received
debug2: set
newkeys: mode 0
debug1: rekey after 134217728 blocks
debug2: key: /Users/flowen/.ssh/idrsa (0x7f8a2b500cb0), explicit
debug3: send packet: type 5
debug3: receive packet: type 6
debug2: service
accept: ssh-userauth
debug1: SSH2MSGSERVICEACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod
lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethodisenabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/flowen/.ssh/idrsa
debug3: send
pubkeytest
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug2: we did not send a packet, disable method
debug3: authmethod
lookup password
debug3: remaining preferred: ,password
debug3: authmethodisenabled password
debug1: Next authentication method: password
lowenf@178.62.186.144's password:

1 Answer

Hi @lowen.f
Seems like your key has changed, or become corrupted, on your local machine.
Try copying the current key from your computer to the droplet again:

ssh-copy-id -P 1526 lowenf@178.62.186.144
Have another answer? Share your knowledge.