SCP Error

[ShawnKST]

Hi All
I am trying to use WINSCP version 5.17.5 to access my 6450 switch using SCP file protocol. When I key in the username and password and upon authentication I receive an error

Remote side send disconnect message
type 2 (Protocol error)
"channel_pre_open:Read fd cannot be set for nonexistent FD -1"
Authentication log (see session log for details):
Using username "admin"
Authentication failed

When I use the same WINSCP application and try to login using SFTP with the same set of credential I have no issue accessing the switch and I have check that SCP is enable in the switch. I have try creating a new admin account, reboot the switch but it doesn't solve the issue
Switch firmware is 6.7.2.122.R08

[ShawnKST]

Hi All
attached are the logs from the event, appreciate if anyone has any idea what is happening
2022-05-04 09:07:40.983 --------------------------------------------------------------------------
. 2022-05-04 09:07:41.014 Looking up host "10.105.0.11" for SSH connection
. 2022-05-04 09:07:41.014 Connecting to 10.105.0.11 port 22
. 2022-05-04 09:07:41.139 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:41.139 We claim version: SSH-2.0-WinSCP_release_5.17.5
. 2022-05-04 09:07:41.139 Detected network event
. 2022-05-04 09:07:41.311 Detected network event
. 2022-05-04 09:07:41.311 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:41.311 Remote version: SSH-2.0-OpenSSH_5.0
. 2022-05-04 09:07:41.311 We believe remote version has SSH-2 channel request bug
. 2022-05-04 09:07:41.311 Using SSH protocol version 2
. 2022-05-04 09:07:41.327 No GSSAPI security context available
. 2022-05-04 09:07:41.327 Have a known host key of type ecdsa-sha2-nistp256
. 2022-05-04 09:07:41.342 Detected network event
. 2022-05-04 09:07:41.342 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:41.452 Detected network event
. 2022-05-04 09:07:41.452 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:41.452 Doing ECDH key exchange with curve nistp256 and hash SHA-256
. 2022-05-04 09:07:41.764 Detected network event
. 2022-05-04 09:07:41.764 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:41.842 Server also has ssh-rsa/ssh-dss host keys, but we don't know any of them
. 2022-05-04 09:07:41.842 Host key fingerprint is:
. 2022-05-04 09:07:41.842 ecdsa-sha2-nistp256 256 0b:71:84:e4:c4:7a:09:58:18:46:e9:89:e6:4f:9e:5b DZXmM1Ei58mlm+HBIXswME3U+7Q0VRof3riLPojnI14=
. 2022-05-04 09:07:41.842 Verifying host key ecdsa-sha2-nistp256 nistp256,0xebcc638c9aa82872 82d1f64c46511445 de91187b6b9e03b4 16d987628a1f2064 ,0x5040dcffdac02a4c 9608b0be26059c77 38b8900b72eeff29 b782df801e94e905 with fingerprints ecdsa-sha2-nistp256 256 0b:71:84:e4:c4:7a:09:58:18:46:e9:89:e6:4f:9e:5b DZXmM1Ei58mlm+HBIXswME3U+7Q0VRof3riLPojnI14=
. 2022-05-04 09:07:41.889 Host key matches cached key
. 2022-05-04 09:07:41.889 Initialised AES-256 SDCTR (AES-NI accelerated) outbound encryption
. 2022-05-04 09:07:41.889 Initialised HMAC-SHA-256 outbound MAC algorithm
. 2022-05-04 09:07:41.889 Initialised AES-256 SDCTR (AES-NI accelerated) inbound encryption
. 2022-05-04 09:07:41.889 Initialised HMAC-SHA-256 inbound MAC algorithm
. 2022-05-04 09:07:41.983 Detected network event
. 2022-05-04 09:07:41.983 Waiting for the server to continue with the initialization
! 2022-05-04 09:07:41.983 Using username "admin".
. 2022-05-04 09:07:42.108 Detected network event
. 2022-05-04 09:07:42.108 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:42.108 Server offered these authentication methods: publickey,password,keyboard-interactive
. 2022-05-04 09:07:42.108 Attempting keyboard-interactive authentication
. 2022-05-04 09:07:42.186 Detected network event
. 2022-05-04 09:07:42.186 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:42.186 Prompt (keyboard interactive, "SSH server authentication", <no instructions>, "admin's password for keyboard-interactive method: ")
. 2022-05-04 09:07:42.186 Using stored password.
. 2022-05-04 09:07:42.514 Detected network event
. 2022-05-04 09:07:42.514 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:42.514 Access granted
. 2022-05-04 09:07:42.514 Opening main session channel
. 2022-05-04 09:07:42.608 Detected network event
. 2022-05-04 09:07:42.608 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:42.608 Opened main channel
. 2022-05-04 09:07:42.686 Detected network event
. 2022-05-04 09:07:42.686 Waiting for the server to continue with the initialization
. 2022-05-04 09:07:42.686 Remote side sent disconnect message type 2 (protocol error): "channel_pre_open:Read fd cannot be set for nonexistent Fd -1."
* 2022-05-04 09:07:42.702 (EFatal) Remote side sent disconnect message
* 2022-05-04 09:07:42.702 type 2 (protocol error):
* 2022-05-04 09:07:42.702 "channel_pre_open:Read fd cannot be set for nonexistent Fd -1."
* 2022-05-04 09:07:42.702 Authentication log (see session log for details):
* 2022-05-04 09:07:42.702 Using username "admin".
* 2022-05-04 09:07:42.702
* 2022-05-04 09:07:42.702 Authentication failed.

[fl0rent]

Hello,

same issue here with a WinSCP 5.21.7 (last one available)
Remote device working with SFTP but not with SCP.
SSH with PuTTy is ok.
Same credentials use.

Remote device got ecdsa-sha2-nistp256 256 which is listed in https://winscp.net/eng/docs/ssh_algorithms

Switch firmware Software Version 6.7.2.89.R06 GA, April 09, 2019