OpenSSH 6.4 connection to Cisco 6506 routers/switches fails

mikep at noc.utoronto.ca mikep at noc.utoronto.ca
Wed Nov 13 08:40:47 EST 2013


Just upgraded to OpenSSH_6.4 with OpenSSL 1.0.1e and libz.so.1.2.8.
Now some (but not all) Cisco router logins hang:

kraken> ssh -vv -l noc XXX-mgmt.gw
OpenSSH_6.4, OpenSSL 1.0.1e 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 50: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to XXX-mgmt.gw [10.12.0.1] port 22.
debug1: Connection established.
debug1: could not open key file '/etc/ssh/ssh_host_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_dsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_ecdsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_rsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_dsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_ecdsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_rsa_key': Permission denied
debug1: identity file /home/mikep/.ssh/id_rsa type -1
debug1: identity file /home/mikep/.ssh/id_rsa-cert type -1
debug1: identity file /home/mikep/.ssh/id_dsa type -1
debug1: identity file /home/mikep/.ssh/id_dsa-cert type -1
debug1: identity file /home/mikep/.ssh/id_ecdsa type -1
debug1: identity file /home/mikep/.ssh/id_ecdsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.4
debug1: Remote protocol version 1.99, remote software version Cisco-1.25
debug1: no match: Cisco-1.25
debug2: fd 4 setting O_NONBLOCK
debug2: key_type_from_name: unknown key type '2048'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: 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: kex_parse_kexinit: ssh-rsa-cert-v01 at openssh.com,ssh-rsa-cert-v00 at openssh.com,ssh-rsa,ecdsa-sha2-nistp256-cert-v01 at openssh.com,ecdsa-sha2-nistp384-cert-v01 at openssh.com,ecdsa-sha2-nistp521-cert-v01 at openssh.com,ssh-dss-cert-v01 at openssh.com,ssh-dss-cert-v00 at openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm at openssh.com,aes256-gcm at openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc at lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-gcm at openssh.com,aes256-gcm at openssh.com,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc at lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-ripemd160-etm at openssh.com,hmac-sha1-96-etm at openssh.com,hmac-md5-96-etm at openssh.com,hmac-md5,hmac-sha1,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160 at openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-ripemd160-etm at openssh.com,hmac-sha1-96-etm at openssh.com,hmac-md5-96-etm at openssh.com,hmac-md5,hmac-sha1,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160 at openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib at openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib at openssh.com,zlib
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: kex_parse_kexinit: diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: hmac-sha1,hmac-sha1-96,hmac-md5,hmac-md5-96
debug2: kex_parse_kexinit: hmac-sha1,hmac-sha1-96,hmac-md5,hmac-md5-96
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-cbc hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-cbc hmac-md5 none
debug2: dh_gen_key: priv key bits set: 129/256
debug2: bits set: 481/1024
debug1: sending SSH2_MSG_KEXDH_INIT
debug1: expecting SSH2_MSG_KEXDH_REPLY
  [hangs]
^C

Originally I had 'Cipher blowfish' set in '/etc/ssh/ssh_config', but
removing that makes no difference. However, forcing '-c 3des' does
allow it to work (even though '3des' is supposed to be the default):

kraken> ssh -vv -c 3des -l noc XXX-mgmt.gw
OpenSSH_6.4, OpenSSL 1.0.1e 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 50: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to XXX-mgmt.gw [10.12.0.1] port 22.
debug1: Connection established.
debug1: could not open key file '/etc/ssh/ssh_host_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_dsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_ecdsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_rsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_dsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_ecdsa_key': Permission denied
debug1: could not open key file '/etc/ssh/ssh_host_rsa_key': Permission denied
debug1: identity file /home/mikep/.ssh/id_rsa type -1
debug1: identity file /home/mikep/.ssh/id_rsa-cert type -1
debug1: identity file /home/mikep/.ssh/id_dsa type -1
debug1: identity file /home/mikep/.ssh/id_dsa-cert type -1
debug1: identity file /home/mikep/.ssh/id_ecdsa type -1
debug1: identity file /home/mikep/.ssh/id_ecdsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.4
debug1: Remote protocol version 1.99, remote software version Cisco-1.25
debug1: no match: Cisco-1.25
debug2: fd 4 setting O_NONBLOCK
debug2: key_type_from_name: unknown key type '2048'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: 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: kex_parse_kexinit: ssh-rsa-cert-v01 at openssh.com,ssh-rsa-cert-v00 at openssh.com,ssh-rsa,ecdsa-sha2-nistp256-cert-v01 at openssh.com,ecdsa-sha2-nistp384-cert-v01 at openssh.com,ecdsa-sha2-nistp521-cert-v01 at openssh.com,ssh-dss-cert-v01 at openssh.com,ssh-dss-cert-v00 at openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-dss
debug2: kex_parse_kexinit: 3des-cbc
debug2: kex_parse_kexinit: 3des-cbc
debug2: kex_parse_kexinit: hmac-md5-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-ripemd160-etm at openssh.com,hmac-sha1-96-etm at openssh.com,hmac-md5-96-etm at openssh.com,hmac-md5,hmac-sha1,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160 at openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5-etm at openssh.com,hmac-sha1-etm at openssh.com,umac-64-etm at openssh.com,umac-128-etm at openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at openssh.com,hmac-ripemd160-etm at openssh.com,hmac-sha1-96-etm at openssh.com,hmac-md5-96-etm at openssh.com,hmac-md5,hmac-sha1,umac-64 at openssh.com,umac-128 at openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160 at openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib at openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib at openssh.com,zlib
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: kex_parse_kexinit: diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
debug2: kex_parse_kexinit: hmac-sha1,hmac-sha1-96,hmac-md5,hmac-md5-96
debug2: kex_parse_kexinit: hmac-sha1,hmac-sha1-96,hmac-md5,hmac-md5-96
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: none
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: mac_setup: found hmac-md5
debug1: kex: server->client 3des-cbc hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server 3des-cbc hmac-md5 none
debug2: dh_gen_key: priv key bits set: 173/384
debug2: bits set: 495/1024
debug1: sending SSH2_MSG_KEXDH_INIT
debug1: expecting SSH2_MSG_KEXDH_REPLY
debug1: Server host key: RSA 98:1d:9c:e1:5b:20:a5:8e:95:5e:02:be:12:4b:f4:0c
debug2: key_type_from_name: unknown key type '2048'
debug2: key_type_from_name: unknown key type '2048'
debug1: Host 'XXX-mgmt.gw' is known and matches the RSA host key.
debug1: Found key in /etc/ssh/ssh_known_hosts:455
debug2: bits set: 488/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/mikep/.ssh/id_rsa (0),
debug2: key: /home/mikep/.ssh/id_dsa (0),
debug2: key: /home/mikep/.ssh/id_ecdsa (0),
              ___
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`-....-'`------)))`=-'"`'"

*******************************************************************************
*              This computer system is operated on behalf of the              *
*                        University of Toronto - CANADA                       *
*                                                                             *
* Only authorised users are entitled to connect and/or login to this computer *
* system.  If you are not  sure whether you are  authorised, then you are not *
* and should DISCONNECT IMMEDIATELY.                                          *
*******************************************************************************
debug1: Authentications that can continue: keyboard-interactive,password
debug1: Next authentication method: keyboard-interactive
debug2: userauth_kbdint
debug2: we sent a keyboard-interactive packet, wait for reply
debug2: input_userauth_info_req
debug2: input_userauth_info_req: num_prompts 1
Password:

'/etc/ssh/ssh_config' contents:

Host *
   ForwardAgent yes
   ForwardX11 yes
   ForwardX11Trusted yes
   RhostsRSAAuthentication yes
   HostbasedAuthentication yes
   AddressFamily inet
   EnableSSHKeysign yes
   StrictHostKeyChecking ask
   Protocol 2
   PreferredAuthentications hostbased,publickey,keyboard-interactive,password
   UsePrivilegedPort yes

Previous version (openssh-5.9p1 with OpenSSL 1.0.1e and zlib-1.2.3) worked 
fine, with added 'Cipher blowfish' in the '/etc/ssh/ssh_config' file.

Thanks for any hints!

Mike
--
Mike Peterson                            Information Security Analyst - Audit
E-mail: mikep at noc.utoronto.ca                WWW: http://www.noc.utoronto.ca/
Tel: 416-978-5230                                           Fax: 416-978-6620


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