PowerShell / PowerShell/Win32-OpenSSH

Non-printing character spam when connected to Win2019 ssh server.

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Description

Troubleshooting steps
Checked..

Terminal issue? please go through wiki
Checked.

"OpenSSH for Windows" version
8.1.0.0

Server OperatingSystem
Windows Server 2019 Standard
en_windows_server_2019_updated_june_2020_x64
en_windows_server_2019_updated_march_2020_x64

Client OperatingSystem
CentOS 6.10:
$ ssh -V
OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013

CentOS 7.8:
$ /usr/bin/ssh -V
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips 26 Jan 2017

CentOs 8.1
$ /usr/bin/ssh -V
OpenSSH_8.0p1, OpenSSL 1.1.1c FIPS 28 May 2019

What is failing
We are maintaining the same sshd config on both Windows 2016 and Windows 2019. When linux ssh clients attach to a Windows 2016 server we get no repeating non-printing character spam, but on Windows 2019 we get an endless amount of "^[[153X^[[153C^M"
Where "153" is the column size of the xterm.
This makes thing difficult for expect scripts and does not occur on Windows 2016.

For example:

$ script
Script started, file is typescript
$ ssh administrator@chug09
administrator@chug09's password:
Microsoft Windows [Version 10.0.17763.1282]
(c) 2018 Microsoft Corporation. All rights reserved.

CHUG09# exit
Connection to chug09 closed.
$ exit
exit
Script done, file is typescript


The contents of the typescript file:

Script started on Mon 06 Jul 2020 05:41:27 PM PDT
$ ssh administrator@chug09^M
administrator@chug09's password: ^M
^[[2J^[[?25l^[[m^[[H^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^M
^[[H^[]0;c:\windows\system32\cmd.exe^@^G^[[?25h^[[?25lMicrosoft Windows [Version 10.0.17763.1282]^[[110X^[[110C^M
(c) 2018 Microsoft Corporation. All rights reserved.^[[101X^[[101C^M
^[[153X^[[153C^M
CHUG09#^[[146X^[[146C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
^[[153X^[[153C^M
...
...
...

I know, I know...I likely need to report this to Microsoft, but thought you all might have some insight. Thanks.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the SSH connection with the listed CentOS clients against Windows Server 2016 and 2019, capturing the terminal output as shown. Compare the emitted escape sequences and terminal dimensions; done means the Windows 2019 session no longer produces repeated non-printing-character spam that disrupts scripts.

Written by the indexing model from the issue text.

Assessment

Tech stack
linux
Domain
networking, operating-systems
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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