ssh no longer works after post windows update restart

[torstees]

Environment

10.0.19041.0

Windows build number: [run `[Environment]::OSVersion` for powershell, or `ver` for cmd]
Your Distribution version: [On Debian or Ubuntu run `lsb_release -r` in WSL]
Whether the issue is on WSL 2 and/or WSL 1: [run `cat /proc/version` in WSL]

Steps to reproduce

Launch WSL 1 (Ubuntu-20.04), run sudo service ssh start

attempt to log into system either from localhost or from a machine on the network. This worked fine before the reboot required by the most recent .NET install. Though, windows update did also install a few other things like security updates.

I tried turning all 3 parts of windows firewall off, but the behavior didn't change.

$ sudo service ssh start

• Starting OpenBSD Secure Shell server sshd /etc/ssh/sshd_config line 16: Deprecated option UsePrivilegeSeparation
  /etc/ssh/sshd_config line 19: Deprecated option KeyRegenerationInterval
  /etc/ssh/sshd_config line 20: Deprecated option ServerKeyBits
  /etc/ssh/sshd_config line 31: Deprecated option RSAAuthentication
  /etc/ssh/sshd_config line 38: Deprecated option RhostsRSAAuthentication
  [ OK ]
  (base) est@~ $ ssh localhost -vvvvv
  OpenSSH_8.2p1 Ubuntu-4ubuntu0.1, OpenSSL 1.1.1f 31 Mar 2020
  debug1: Reading configuration data /etc/ssh/ssh_config
  debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
  debug1: /etc/ssh/ssh_config line 21: Applying options for *
  debug2: resolving "localhost" port 22
  debug2: ssh_connect_direct
  debug1: Connecting to localhost [127.0.0.1] port 22.
  debug1: Connection established.
  debug1: identity file /home/est/.ssh/id_rsa type 0
  debug1: identity file /home/est/.ssh/id_rsa-cert type -1
  debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.1
  kex_exchange_identification: Connection closed by remote host
  (base) est@~ $ sudo service ssh status

lxcore-logs.zip

Expected behavior

I should be able to ssh into this machine

Actual behavior

SSH doesn't work

[therealkenc]

10.0.19041.0
Launch WSL 1 (Ubuntu-20.04)

Can't reproduce here on 20180, WSL1, Ubuntu-20.04.

Might be #4898, but I didn't dive enough to confirm (mostly because it worked).

It probably isn't the Windows Update. Or at least, not without some additional unknown external factor contributing to the fail. If it is the Windows Update, there will be a flood of me2s soon enough (but that seems less likely until they arrive).

A couple of things to try:

• Set PasswordAuthentication yes in /etc/ssh/sshd_config to see if you can connect without the key exchange.
• Install a fresh 18.04 from the Store and see if it is okay there.

[torstees]

So, password authentication was already enabled and 18.04 behaved the same after I installed it. However, uninstalling two Windows Updates from Jun 21 (computer hadn't been restarted until this morning) and manually shutting down WSL did work. So, things are good now.

[therealkenc]

uninstalling two Windows Updates from Jun 21

What were the updates you uninstalled.

[torstees]

Sadly, I didn't write down the numbers, but they were the only two windows updates that were installed on Jun 21 (probably when my the window I had instructed windows not to install updates had ended) so whatever would have become available once it was allowed to look for updates. I tried to find references to 'uninstall' in Application events, but nothing shows up. Do you have a way to find out without turning windows update back on? They were not marked as security updates nor were they .net updates, but regular windows updates.

[therealkenc]

Alright, thanks. Glad you are unblocked.