topic Re: ssh problem in Operating System - HP-UX

ssh problem

Saraswathy_1 — Sun, 01 Jan 2006 14:37:16 GMT

We have secured shell client in our nerwork.
Suddenly from this morning its giving problem for one user.
The problem is while doing ssh from production box to test box shell is prompting for passwd.Not sure what has happened.
None of the file has been changed.
Moreover for other users its working fine.

Re: ssh problem

Patrick Wallek — Sun, 01 Jan 2006 14:57:14 GMT

Check /var/adm/syslog on the destination and see what kind of information is being logged.

You could also try 'ssh -vvv sys_name' to more verbose messages when doing the ssh to the other system.

Re: ssh problem

Saraswathy_1 — Sun, 01 Jan 2006 15:08:35 GMT

syslog on traget server:-

Jan 1 12:01:10 server1 sshd[2278]: error: PAM: Authentication failed for bv from server1

From Source I executed ssh -v

$ssh -v server1
OpenSSH_3.8, OpenSSL 0.9.7d 17 Mar 2004
HP-UX_Secure_Shell-A.03.81.002, HP_UX Secure Shell version
debug1: Reading configuration data /opt/ssh/etc/ssh_config
debug1: Connecting to server1 [12.23.45.5] port 22.
debug1: Connection established.
debug1: identity file /home/bv/.ssh/id_rsa type 1
debug1: identity file /home/bv/.ssh/id_dsa type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_3.8
debug1: match: OpenSSH_3.8 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.8
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'shm3sc1' is known and matches the RSA host key.
debug1: Found key in /home/bv/.ssh/known_hosts:87
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Offering public key: /home/bv/.ssh/id_rsa
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Trying private key: /home/bv/.ssh/id_dsa
debug1: Next authentication method: keyboard-interactive
Password:

Lastly prompting for passwd.
Not sure were is the problem. Please advice in this matter.

Re: ssh problem

Bill Hassell — Sun, 01 Jan 2006 19:24:00 GMT

For an automated login (ie, no password), both computers must have they keys setup. If this was working, someone has probably changed the keyfile, moved or removed the file, or perhaps the user is logging in under a different account. Was anything restored to either system from backup? It's possibile that an old copy of the file replaced the latest version.

Re: ssh problem

Muthukumar_5 — Mon, 02 Jan 2006 03:22:29 GMT

Is there anything in /etc/pam_user.conf file. May be because of key file moving or renaming or content change. Try to recreate key for that user.

-Muthu

Re: ssh problem

Michael Selvesteen_2 — Mon, 02 Jan 2006 05:18:37 GMT

Hi,

You can try the following

1. Check the Permissions of the both private and public keys (644 for /home/bv/.ssh/id_rsa.pub & 600 for /home/bv/.ssh/id_rsa).

2. Ensure the server supports publickey authentication ( check Publickeyauthentication is yes in sshd_config )

Post the server log ( /opt/ssh/sbin/sshd -ddde ) if possible for more analysis

All the best

Re: ssh problem

Saraswathy_1 — Mon, 02 Jan 2006 06:21:25 GMT

Here is the server log.

/opt/ssh/sbin/sshd -ddde
debug3: Seeding PRNG from /opt/ssh/libexec/ssh-rand-helper
debug2: read_server_config: filename /opt/ssh/etc/sshd_config
debug1: sshd version OpenSSH_3.8 [ HP-UX_Secure_Shell-A.03.81.002 ]
Could not load host key: /opt/ssh/etc/ssh_host_key
Could not load host key: /opt/ssh/etc/ssh_host_rsa_key
Could not load host key: /opt/ssh/etc/ssh_host_dsa_key
Disabling protocol version 2. Could not load host key
sshd: no hostkeys available -- exiting.

Could some one clarify which is server and client.Moreover I need only one way communication with out passwd.

Please advice

Re: ssh problem

Bill Hassell — Mon, 02 Jan 2006 09:32:07 GMT

It looks like someone has removed your keyfile:

Could not load host key: /opt/ssh/etc/ssh_host_key
Could not load host key: /opt/ssh/etc/ssh_host_rsa_key
Could not load host key: /opt/ssh/etc/ssh_host_dsa_key
Disabling protocol version 2. Could not load host key

Clients and server are defined the same way as for telnet or other connections. The user typing on the keyboard is the client (clients start the connection) and the server is the remote system that you want to contact.

You'll need to rebuild (or restore from backup) the keyfile on the server (the remote side).

Re: ssh problem

Sivakumar TS — Mon, 02 Jan 2006 11:05:04 GMT

Dear Saraswathy,

Check this link,

http://cc.in2p3.fr/doc/phpman.php/man/ssh-keysign/8

Hope this helps.

With Regards,

Siva.

Re: ssh problem

Michael Selvesteen_2 — Tue, 03 Jan 2006 03:58:46 GMT

Hi Again,

As you lost your host keys you can try the following

1. If you have a backup of host keys you can replace with correct permissions

2. If possible try re-installing the HP Secure Shell

For more information about Hostkey and public key(password less) authentication you can refer the following link

http://cfm.gs.washington.edu/security/ssh/client-pkauth/

you can also find some useful information from /opt/ssh/README.hp and HP Secure Shell release notes

All the Best

Re: ssh problem

Saraswathy_1 — Tue, 03 Jan 2006 06:11:02 GMT

FYI:- For other users I do not have any problem. Only for one user Iam facing this problem.
From client only for one user shell is prompting password. Others are fine.