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SSH password authentication in Java using jcraft JSch fails with “Auth fail” but command-line “ssh” works

My system’s OS is Ubuntu 18. I am trying to connect SFTP through Java jcraft JSch but facing this exception:

com.jcraft.jsch.JSchException: Auth fail

Below are working:

  1. From terminal using sftp works fine with username and password, no issues.
  2. From FileZilla also it is working fine.

Maven Dependency:

<dependency>
    <groupId>com.jcraft</groupId>
    <artifactId>jsch</artifactId>
    <version>0.1.54</version>
</dependency>
String username = "xx_xxxxx";
String password = "xxxxxxx";
String host = "xxxxx-xx.xxxx.org";
JSch jsch = new JSch();
Session jschSession = jsch.getSession(username, host, 22);
java.util.Properties config = new java.util.Properties();
config.put("StrictHostKeyChecking", "no");
config.put("PreferredAuthentications", "password");

System.out.println(jschSession.getHost());
jschSession.setConfig(config);
jschSession.setPassword(password);
jschSession.connect(10000);
return (ChannelSftp) jschSession.openChannel("sftp");

Output:

com.jcraft.jsch.JSchException: Auth fail
    at com.jcraft.jsch.Session.connect(Session.java:473)
    at in.serosoft.academia.server.common.FTPDemo.setupJsch(FTPDemo.java:118)
    at in.serosoft.academia.server.common.FTPDemo.uploadSftpFromPath(FTPDemo.java:125)
    at in.serosoft.academia.server.common.FTPDemo.main(FTPDemo.java:187)
java.lang.NullPointerException
    at in.serosoft.academia.server.common.FTPDemo.uploadSftpFromPath(FTPDemo.java:131)
    at in.serosoft.academia.server.common.FTPDemo.main(FTPDemo.java:187)

Terminal command sftp -vvv output:

OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n  7 Dec 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "xxxxx-xx.xxxx.xxx" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to xxxxx-xx.xxxx.xxx [xxx.xx.xx.xxx] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/xxxx-xxxxx/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/xxxx-xxxxx/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/xxxx-xxxxx/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/xxxx-xxxxx/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/xxxx-xxxxx/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/xxxx-xxxxx/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/xxxx-xxxxx/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/xxxx-xxxxx/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to xxxxx-xx.xxxx.xxx:22 as 'yy_yyyyy'
debug3: hostkeys_foreach: reading file "/home/xxxx-xxxxx/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/xxxx-xxxxx/.ssh/known_hosts:3
debug3: load_hostkeys: loaded 1 keys from xxxxx-xx.xxxx.xxx
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],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: [email protected],rsa-sha2-512,rsa-sha2-256,ssh-rsa,[email protected],[email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],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,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: rsa-sha2-512
debug1: kex: server->client cipher: aes128-ctr MAC: [email protected] compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: [email protected] compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-rsa SHA256:62WxJjKHYP7fMeSKiEUFjEjKbYU6XWTLBJ1NJiAp0T4
debug3: hostkeys_foreach: reading file "/home/xxxx-xxxxx/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/xxxx-xxxxx/.ssh/known_hosts:3
debug3: load_hostkeys: loaded 1 keys from xxxxx-xx.xxxx.xxx
debug3: hostkeys_foreach: reading file "/home/xxxx-xxxxx/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/xxxx-xxxxx/.ssh/known_hosts:4
debug3: load_hostkeys: loaded 1 keys from xxx.xx.xx.xxx
debug1: Host 'xxxxx-xx.xxxx.xxx' is known and matches the RSA host key.
debug1: Found key in /home/xxxx-xxxxx/.ssh/known_hosts:3
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 4294967296 blocks
debug2: key: /home/xxxx-xxxxx/.ssh/id_rsa ((nil))
debug2: key: /home/xxxx-xxxxx/.ssh/id_dsa ((nil))
debug2: key: /home/xxxx-xxxxx/.ssh/id_ecdsa ((nil))
debug2: key: /home/xxxx-xxxxx/.ssh/id_ed25519 ((nil))
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 53
debug3: input_userauth_banner
Use of this computer system is restricted to OCLC authorized users, who must
comply with the Acceptable Use Policy.  Use and activity may be monitored or
recorded and may be subject to auditing.
 Unauthorized access is strictly prohibited.
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,keyboard-interactive
debug3: start over, passed a different list publickey,keyboard-interactive
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /home/xxxx-xxxxx/.ssh/id_rsa
debug3: no such identity: /home/xxxx-xxxxx/.ssh/id_rsa: No such file or directory
debug1: Trying private key: /home/xxxx-xxxxx/.ssh/id_dsa
debug3: no such identity: /home/xxxx-xxxxx/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /home/xxxx-xxxxx/.ssh/id_ecdsa
debug3: no such identity: /home/xxxx-xxxxx/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /home/xxxx-xxxxx/.ssh/id_ed25519
debug3: no such identity: /home/xxxx-xxxxx/.ssh/id_ed25519: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup keyboard-interactive
debug3: remaining preferred: password
debug3: authmethod_is_enabled keyboard-interactive
debug1: Next authentication method: keyboard-interactive
debug2: userauth_kbdint
debug3: send packet: type 50
debug2: we sent a keyboard-interactive packet, wait for reply
debug3: receive packet: type 60
debug2: input_userauth_info_req
debug2: input_userauth_info_req: num_prompts 1
Password: 
debug3: send packet: type 61
Connection closed by xxx.xx.xx.xxx port 22
Connection closed

sftp -o "PreferredAuthentications password" -vvv [email protected] Output:

OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n  7 Dec 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "xxxx-xx.xxxx.xxx" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to xxxx-xx.xxxx.xxx [113.29.23.198] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/zzzzz-zzzzzz/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/zzzzz-zzzzzz/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/zzzzz-zzzzzz/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/zzzzz-zzzzzz/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/zzzzz-zzzzzz/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/zzzzz-zzzzzz/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/zzzzz-zzzzzz/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/zzzzz-zzzzzz/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to xxxx-xx.xxxx.xxx:22 as 'yy_yyyyy'
debug3: hostkeys_foreach: reading file "/home/zzzzz-zzzzzz/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/zzzzz-zzzzzz/.ssh/known_hosts:3
debug3: load_hostkeys: loaded 1 keys from xxxx-xx.xxxx.xxx
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],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: [email protected],rsa-sha2-512,rsa-sha2-256,ssh-rsa,[email protected],[email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],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,diffie-hellman-group1-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: rsa-sha2-512
debug1: kex: server->client cipher: aes128-ctr MAC: [email protected] compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: [email protected] compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ssh-rsa SHA256:62WxJjKHYP7fMeSKiEUFjEjKbYU6XWTLBJ1NJiAp0T4
debug3: hostkeys_foreach: reading file "/home/zzzzz-zzzzzz/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/zzzzz-zzzzzz/.ssh/known_hosts:3
debug3: load_hostkeys: loaded 1 keys from xxxx-xx.xxxx.xxx
debug3: hostkeys_foreach: reading file "/home/zzzzz-zzzzzz/.ssh/known_hosts"
debug3: record_hostkey: found key type RSA in file /home/zzzzz-zzzzzz/.ssh/known_hosts:4
debug3: load_hostkeys: loaded 1 keys from 113.29.23.198
debug1: Host 'xxxx-xx.xxxx.xxx' is known and matches the RSA host key.
debug1: Found key in /home/zzzzz-zzzzzz/.ssh/known_hosts:3
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 4294967296 blocks
debug2: key: /home/zzzzz-zzzzzz/.ssh/id_rsa ((nil))
debug2: key: /home/zzzzz-zzzzzz/.ssh/id_dsa ((nil))
debug2: key: /home/zzzzz-zzzzzz/.ssh/id_ecdsa ((nil))
debug2: key: /home/zzzzz-zzzzzz/.ssh/id_ed25519 ((nil))
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 53
debug3: input_userauth_banner
Use of this computer system is restricted to OCLC authorized users, who must
comply with the Acceptable Use Policy.  Use and activity may be monitored or
recorded and may be subject to auditing.
 Unauthorized access is strictly prohibited.
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,keyboard-interactive
debug3: start over, passed a different list publickey,keyboard-interactive
debug3: preferred password
debug1: No more authentication methods to try.
[email protected]: Permission denied (publickey,keyboard-interactive).
Connection closed

Answer

Your ssh uses keyboard interactive authentication. The password authentication does not seem to work on your server. So you need to do the same with JSch.

See the official UserAuthKI example.

Basically you need to implement the UIKeyboardInteractive interface (together with the UserInfo interface) and associate the implementation with the session using the Session.setUserInfo.

If the authentication is prompting for a single “password” only, implement the UIKeyboardInteractive.promptKeyboardInteractive method to return a single element array with the password.


Obligatory warning: Do not use StrictHostKeyChecking=no to blindly accept all host keys. That is a security flaw. You lose a protection against MITM attacks. For the correct (and secure) approach, see: How to resolve Java UnknownHostKey, while using JSch SFTP library?