How to set Openssh and Mit kerberos (from windows to linux server)?
I need to connect through openssh from windows to a linux server using a kerberos ticket. I got the bin file from: https://github.com/NoMoreFood/openssh-portable/releases/tag/v7.9-sspi
Through my company login UI, I obtain the ticket using MIT Kerberos. If I Run
klist
this is the output
Ticket cache: FILE:C:\Users\Test\....\host.domain.subdomain.local
Default principal: USER@REALM
Valid starting Expires Service principal
09/23/19 16:18:53 09/23/19 19:18:53 krbtgt/REALM@REALM
09/23/19 16:18:56 09/23/19 19:18:53 krbtgt/DOMAIN@REALM
09/23/19 16:18:56 09/23/19 19:18:53 host/host.domain.subdomain.local@DOMAIN
With Putty I have no problem to connect. So I tried with openssh binary:
ssh -Kvvv USER@HOST
where the config file is
Host HOST
GSSAPIDelegateCredentials yes
GSSAPIAuthentication yes
I reach the server but it asks me the password and doesn't send the kerberos ticket
And this is the log
OpenSSH_for_Windows_7.9p1, LibreSSL 2.6.4
debug1: Reading configuration data C:\\Users\\Test/.ssh/config
debug1: C:\\Users\\Test/.ssh/config line 7: Applying options for HOST
debug3: Failed to open file:C:/ProgramData/ssh/ssh_config error:2
debug2: resolving HOST port 22
debug2: ssh_connect_direct
debug1: Connecting to HOST [ip] port 22.
debug1: Connection established.
debug3: Failed to open file:C:/Users/Test/.ssh/id_rsa error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_rsa.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_rsa type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_rsa-cert error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_rsa-cert.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_rsa-cert type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_dsa error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_dsa.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_dsa type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_dsa-cert error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_dsa-cert.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_dsa-cert type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_ecdsa error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_ecdsa.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_ecdsa type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_ecdsa-cert error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_ecdsa-cert.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_ecdsa-cert type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_ed25519 error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_ed25519.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_ed25519 type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_ed25519-cert error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_ed25519-cert.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_ed25519-cert type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_xmss error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_xmss.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_xmss type -1
debug3: Failed to open file:C:/Users/Test/.ssh/id_xmss-cert error:2
debug3: Failed to open file:C:/Users/Test/.ssh/id_xmss-cert.pub error:2
debug1: identity file C:\\Users\\Test/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_for_Windows_7.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to HOST:22 as USER
debug3: hostkeys_foreach: reading file "C:\\Users\\Test/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file C:\\Users\\Test/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from HOST
debug3: Failed to open file:C:/Users/Test/.ssh/known_hosts2 error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts2 error:2
debug3: order_hostkeyalgs: prefer hostkeyalgs: [..]
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: [...]
debug2: host key algorithms: [...]
debug2: ciphers ctos: [...]
debug2: ciphers stoc: [...]
debug2: MACs ctos: [...]
debug2: MACs stoc: [...]
debug2: compression ctos: none
debug2: compression stoc: none
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: [...]
debug2: host key algorithms: [...]
debug2: ciphers ctos: [...]
debug2: ciphers stoc: [...]
debug2: MACs ctos: [...]
debug2: MACs stoc: [...]
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: 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
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: [...]
debug3: hostkeys_foreach: reading file "C:\\Users\\Test/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file C:\\Users\\Test/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from HOST
debug3: Failed to open file:C:/Users/Test/.ssh/known_hosts2 error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts2 error:2
debug3: hostkeys_foreach: reading file "C:\\Users\\Test/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file C:\\Users\\Test/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from IP
debug3: Failed to open file:C:/Users/Test/.ssh/known_hosts2 error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts error:2
debug3: Failed to open file:C:/ProgramData/ssh/ssh_known_hosts2 error:2
debug1: Host HOST is known and matches the ECDSA host key.
debug1: Found key in C:\\Users\\Test/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 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 134217728 blocks
debug3: unable to connect to pipe \\\\.\\pipe\\openssh-ssh-agent, error: 2
debug1: pubkey_prepare: ssh_get_authentication_socket: No such file or directory
debug1: Will attempt key: C:\\Users\\Test/.ssh/id_rsa
debug1: Will attempt key: C:\\Users\\Test/.ssh/id_dsa
debug1: Will attempt key: C:\\Users\\Test/.ssh/id_ecdsa
debug1: Will attempt key: C:\\Users\\Test/.ssh/id_ed25519
debug1: Will attempt key: C:\\Users\\Test/.ssh/id_xmss
debug2: pubkey_prepare: done
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
+-----------------------------------------------------------------+
+-----------------------------------------------------------------+
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug3: start over, passed a different list publickey,gssapi-keyex,gssapi-with-mic,password
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup gssapi-with-mic
debug3: remaining preferred: publickey,keyboard-interactive,password
debug3: authmethod_is_enabled gssapi-with-mic
debug1: Next authentication method: gssapi-with-mic
debug1: GSS_S_FAILURE
debug2: we did not send a packet, disable method
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: C:\\Users\\Test/.ssh/id_rsa
debug3: no such identity: C:\\Users\\Test/.ssh/id_rsa: No such file or directory
debug1: Trying private key: C:\\Users\\Test/.ssh/id_dsa
debug3: no such identity: C:\\Users\\Test/.ssh/id_dsa: No such file or directory
debug1: Trying private key: C:\\Users\\Test/.ssh/id_ecdsa
debug3: no such identity: C:\\Users\\Test/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: C:\\Users\\Test/.ssh/id_ed25519
debug3: no such identity: C:\\Users\\Test/.ssh/id_ed25519: No such file or directory
debug1: Trying private key: C:\\Users\\Test/.ssh/id_xmss
debug3: no such identity: C:\\Users\\Test/.ssh/id_xmss: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
debug3: failed to open file:C:/dev/tty error:3
debug1: read_passphrase: can't open /dev/tty: No such file or directory
USER@HOST's password:
EDIT: If I connect with plink everything works
plink -v hostPuttyAlias
Looking up host HOST for SSH connection
Connecting to ip port 22
We claim version: SSH-2.0-PuTTY_Release_0.72
Remote version: SSH-2.0-OpenSSH_7.4
Using SSH protocol version 2
Doing ECDH key exchange with curve Curve25519 and hash SHA-256 (unaccelerated)
Server also has ecdsa-sha2-nistp256 host key, but we don't know it
Host key fingerprint is:
ssh-ed25519 255 [...]
Initialised AES-256 SDCTR (AES-NI accelerated) outbound encryption
Initialised HMAC-SHA-256 (unaccelerated) outbound MAC algorithm
Initialised AES-256 SDCTR (AES-NI accelerated) inbound encryption
Initialised HMAC-SHA-256 (unaccelerated) inbound MAC algorithm
Using username user.
-- Pre-authentication banner message from server: ----------------------------
Using GSSAPI from GSSAPI64.DLL
Trying gssapi-with-mic...
Attempting GSSAPI authentication
-- End of banner message from server -----------------------------------------
GSSAPI authentication initialised
GSSAPI authentication initialised
GSSAPI authentication loop finished OK
Access granted
Access granted. Press Return to begin session.
I'm adding a late answer since this is question is still one of the top google results for connecting to an OpenSSH SSH / SFTP / SCP server via kerberos.
The short answer is try ssh -K MyServer, and be done! The current way to do this in Windows 10/Windows Server only requires:
- Enabling the openssh client tools, or downloading them (if needed).
- A recent version of openssh_for_windows. I'm using 8.1p1 here.
- Running whatever terminal you want to use as the remote user if it's different from your current credentials.
# Check if the openssh tools are present:
Get-WindowsCapability -online -name OpenSSH.Client* | Select State
State : NotPresent
# You may or may not need to restart after enabling the client
Add-WindowsCapability -Online -Name OpenSSH.Client
Online : True
RestartNeeded : False
# Make sure you're running as the correct user:
PS C:\> whoami
domain\MyUser
Then you can connect via kerberos directly. Here's the trimmed-down debug of my connection:
PS C:\> ssh -Kv my-server.domain.tld
OpenSSH_for_Windows_8.1p1, LibreSSL 3.0.2
debug1: Connecting to my-server.domain.tld [10.0.0.1] port 22.
debug1: Connection established.
debug1: Authenticating to my-server.domain.tld:22 as 'MyDomain\\MyUser'
debug1: Next authentication method: gssapi-with-mic
debug1: Authentication succeeded (gssapi-with-mic).
[MyUser@MyServer ~]$
Voilà!
More Details:
A successful connection should create a new kerberos ticket for you to that host if you don't have one. Note that these get flagged as
-
pre_authent, meaning you and the SSH server need to be able to connect to an AD domain controller while establishing the connection. -
forwardable, which allows for authentication forwarding to theServer:ID without requiring a password to be typed in again.
# trimmed klist output on windows after connecting successfully:
PS C:\> klist
#0> Client: MyUser @ DOMAIN.TLD
Server: krbtgt/DOMAIN.TLD @ DOMAIN.TLD
Ticket Flags 0x40e10000 -> forwardable renewable initial pre_authent name_canonicalize
#1> Client: MyUser @ DOMAIN.TLD
Server: host/myserver @ DOMAIN.TLD
Ticket Flags 0x40a10000 -> forwardable renewable pre_authent name_canonicalize
Be aware that these tickets won't allow you to jump again without manually creating a new ticket, e.g.:
# MyLaptop -> MyServer -> MySecureServer
# double-hop prompts for password, fails
PS C:\MyLaptop\> ssh -K MyServer
[myuser@myserver ~]$ ssh -k MySecureServer
myuser@mysecureserver's password:
# Generate a new ticket manually, and success:
PS C:\MyLaptop\> ssh -K MyServer
[myuser@myserver ~]$ kinit
Password for [email protected]:
[myuser@myserver ~]$ ssh -k MySecureServer
[myuser@mysecureserver ~]$
The same rule applies to PS-Sessions.