2FA with SFTP plugin (again)

[sevec]

Hello, I use SFTP plugin 3.05 final with TC 11.56 64bit.
When I try to connect to some server which requires 2FA, I get enter username and enter password dialog box and then “Error: Authentication by keyboard-interactive failed!”

Connecting by a regular ssh client I get

Using username "blabla".
Keyboard-interactive authentication prompts from server:
| Password:
End of keyboard-interactive prompts from server
Further authentication required
Keyboard-interactive authentication prompts from server:
| Your 2nd factor (blabla):
End of keyboard-interactive prompts from server


Could the plugin be somehow told to handle such 2FA and correctly prompt for the 2nd factor?

[ghisler(Author)]

That's odd, the plugin already supports this via Keyboard-interactive, and I have used it myself with my servers.
What server software and configuration do you use?

[sevec]

When I log in using Winscp, it shows
Red Hat Enterprise Linux release 9.7,
File transfer protocol = SFTP-3
Cryptographic protocol = SSH-2
SSH implementation = OpenSSH_8.7
Encryption algorithm = AES-256 SDCTR (AES-NI accelerated)
Compression = No
------------------------------------------------------------
Can change permissions = Yes
Can change ACL = No
Can change owner/group = Yes
Can execute arbitrary command = No
Can create symbolic/hard link = Yes/Yes
Can lookup user groups = No
Can duplicate remote files = No
Can check available space = Yes
Can calculate file checksum = No
Native text (ASCII) mode transfers = No
------------------------------------------------------------
Additional information
The server supports these SFTP extensions:
posix-rename@openssh.com="1"
statvfs@openssh.com="2"
fstatvfs@openssh.com="2"
hardlink@openssh.com="1"
fsync@openssh.com="1"
lsetstat@openssh.com="1"
limits@openssh.com="1"
expand-path@openssh.com="1"
------------------------------------------------------------

[ghisler(Author)]

This server sends two separate keyboard interactive requests, one for the password and one for the second factor, although the function supports multiple requests together.

You need at least version 3.10 beta 8 of the SFTP plugin to support this. From the history:
20250604 Release, version 3.10 beta 9
20250529 Added: Support login with password and second factor, where the server sends two separate requests

You can find it here:
viewtopic.php?p=154999

[sevec]

Thank you very much! It works!