SCP - wrong username

[andreas]

I am using flashfxp with vshell SCP server
When I use a wrong username for the session, flashfxp returns the following error:

[14:28:58] [R] Connecting to WRONG_PASS_SESSION -> DNS=my.server.com IP=192.168.1.10 PORT=22
[14:28:58] [R]
Connected to WRONG_PASS_SESSION [14:28:59] [R] Host key algorithm ssh-rsa, size 2048 bits.
[14:28:59] [R] Fingerprint (MD5): da:00:aa:a3:33:f6:44:11:1b:34:a5:11:11:11:12:22

[14:28:59] [R] Key exchange: diffie-hellman-group-exchange-sha256. Session encryption: aes256-ctr, MAC: hmac-sha1, compression: none.

[14:28:59] [R] Auth Type: Password

*[14:28:59] [R] SSH Error: failed to negotiate authentication method*

[14:28:59] [R] SSH Connection closed [14:28:59] [R] Connection failed


This seems to be wrong.
An error like "Invalid username or password" should be returned, shouldn't it?

[bigstar]

The login failure reply from a SSH server is vague and in most cases doesn't tell you why access was denied, just that access was denied, which could mean a lot of things, such as the user/pass are correct but the user doesn't have access, or that the user is temporarily disabled, or maybe this user can only sign in using public key authentication.

[bigstar]

After some real-world testing and stepping through the code I discovered that there is something wrong.

Good catch.

I am still investigating the issue and will let you know what I find.

[bigstar]

[08:56:40] [R] Key exchange: curve25519-sha256@libssh.org. Session encryption: aes256-ctr, MAC: hmac-sha1, compression: none.
[08:56:40] [R] Auth Type: Password
[08:56:40] [R] Authentication failed [unknown user or invalid password]
[08:56:40] [R] SSH Error: failed to negotiate authentication method
[08:56:40] [R] SSH Connection closed
[08:56:40] [R] Connection failed

Here we go, the correct the result.

The "Authentication failed" line was not being triggered due to an unexpected change in one of the SecureBlackBox updates.

[andreas]

There are the logs from vshell in case they help you

VShellSSH2 conn 8 10.10.10.54 56354 - - - 0 0 0 0 10.10.10.164 22 "00008: Connection accepted from 10.10.10.54:56354"
VShellSSH2 auth 8 - - wrong_user - - 0 0 0 0 - - "00008: Username lookup failed for user wrong_user: No mapping between account names and security IDs was done."
VShellSSH2 auth 8 10.10.10.54 56354 wrong_user - - 0 0 0 0 - - "00008: none for user wrong_user rejected because it is unavailable"
VShellSSH2 auth 8 - - wrong_user - - 0 0 0 0 - - "00008: Authentication for wrong_user failed: The user name or password is incorrect."
VShellSSH2 auth 8 - - wrong_user - - 0 0 0 0 - - "00008: password for user wrong_user rejected"
VShellSSH2 auth 8 10.10.10.54 56354 wrong_user - - 0 0 0 0 10.10.10.164 22 "00008: Authentication failure count for 10.10.10.54 updated to 1 due to authentication failure by user wrong_user"
VShellSSH2 conn 8 - - - - - 0 0 0 0 - - "00008: The transport was aborted with a disconnect packet: Disconnected by application. No more authentication methods available"
VShellSSH2 conn 9 10.10.10.54 56355 - - - 0 0 0 0 10.10.10.164 22 "00009: Connection accepted from 10.10.10.54:56355"
VShellSSH2 auth 9 - - wrong_user - - 0 0 0 0 - - "00009: Username lookup failed for user wrong_user: No mapping between account names and security IDs was done."
VShellSSH2 auth 9 10.10.10.54 56355 wrong_user - - 0 0 0 0 - - "00009: none for user wrong_user rejected because it is unavailable"
VShellSSH2 auth 9 - - wrong_user - - 0 0 0 0 - - "00009: Authentication for wrong_user failed: The user name or password is incorrect."
VShellSSH2 auth 9 - - wrong_user - - 0 0 0 0 - - "00009: password for user wrong_user rejected"
VShellSSH2 auth 9 10.10.10.54 56355 wrong_user - - 0 0 0 0 10.10.10.164 22 "00009: Authentication failure count for 10.10.10.54 updated to 2 due to authentication failure by user wrong_user"
VShellSSH2 conn 9 - - - - - 0 0 0 0 - - "00009: The transport was aborted with a disconnect packet: Disconnected by application. No more authentication methods available"